What are the essentials of chess etiquette in a serious, over-the-board tournament game? I'm asking this question to provide players who are starting to play in tournaments a guide on proper behavior during games. I'll give an answer myself - perhaps we could supply an answer collectively via a community wiki.

First of all, be quiet and don't talk. You can whisper, but it is still considered rude / impolite.

If the round begins at 9AM, be there punctually. In some tournaments you might even lose the game if you're not there within the first 30 minutes.

If the game begins, you can say something like 'I wish us a good game', 'Good Game' and so on.

If something happens on the board and you don't know what to do, you can ask the referee or try to fix it with your opponent.

What is the proper way to ask for a draw?

If there is a big chess game of two big chess players and you want to watch it, don't stand right next to them. Let them have their space. video

If you write your moves down on a piece of paper and you have to give it to the tournament administration, be aware that the result is the same on your slip + the opponent's slip. Both slips also have to be signed by both players.

No smart / cell phones are not allowed during your game (you need to turn them off) and it it also not allowed to turn them on if you watch some games, but you're not playing. The reason is, you could be cheating and some crap like that.

If you want, you can ask your opponent to analyze the game, after it is over.

If you have any further question, just ask.

EDIT:

When you are giving a Check, don't say it. Thanks Akavall

It's also considered poor behavior to eat at the board. Thanks Andrew Ng Of course, you can drink some water or something else, but be aware with the space. Normally the desks aren't that big.


Acknowledging a check mate Do you have to tell someone that they set them selves up for a check mate? For example if the queen is guarding the king on both ends and one person moves there queen to the left. Does the opposite person have to tell the opponent that they set them selves up?

If your question is "Do I have to tell my opponent that he just made a move from where checkmate is forced?", the answer is "No", you don't have to tell your opponent he is setting himself up for checkmate. In fact, that is rather the point of the game!

The only times you have to tell anything to your opponent is:

When offering a draw
When you want to adjust a piece.

If your question is "Do I have to tell my opponent that he is in checkmate?", the answer is still technically "No". Even the customary "Check" and "Checkmate" are optional.

Practically, if your opponent does not grasp that he is in checkmate it may be useful to point that out to him one way or another, and the traditional "Checkmate!" should do the trick.


Studies on how people really improve at chess? How do people really improve at chess?

I often hear people say that any of the following will improve a player's ability:

Doing tactics puzzles
Playing more games
Playing bullet games
Playing longer games
Playing correspondence games
Memorizing openings
Analyzing own games
Reading chess books

Sometimes I hear a specific example like "I've been doing tactics puzzles since last year and it has improved my understanding significantly", and then I ask for their lichess name, and I check it, and their rating has been extremely steady for the last 3 years.

Often these kinds of suggestions seem at first to be anecdotal, but even anecdotes would be true. These are worse than anecdotes because they are not based in reality.

Is there some scientific study of GMs and their history to find out exactly the key points that made them great? Or some study of kids over time with different training techniques and comparison of rating changes to see what works and what doesn't?

As far as I can tell, the thing GMs have in common is that they all had strong chess coaches when they were kids and became very strong players by the time they were 15 or younger.

The closest thing there is to a long term study from child to gm of training techniques would be the polgar sisters. I'd advise searching for information on them to answer your question. Also I'm sure old soviet literature is full of ways to train chess GMs, they specialized in that for many years and had quite a few methods they thought optimally trained young players.

Anecdotally I can tell you from 2000 to 2200 I trained 2 hr 45 minutes on average each day, studying at minimum 10 chess tempo tactics, 3 recent gm games, a gm game of guess the move on chesstempo, and 1 15+ minute game on ICC a day with about an hour spent afterwards studying related games and opening lines. I also participated in an endgame club for about 4 months that year, read through Dvoretskys Endgame Manual, and Endgame Strategy by Mikhail Shereshevsky. At the beginning of that year (first 3 months) I also read through Winning Chess Middlegames by Ivan Sokolov.

For the first 10 months I gained maybe 50 rating points over 3 tournaments. I gained 150 points in 2 tournaments in the last two months.

I think this level of training could probably net 400 points in a year at lower levels, so long as young trainees were given optimum resources to practice with. Often times people use books that are either not suited to their level, don't address their weaknesses, or simple aren't very good. Also people have a tendency to play a lot of blitz or do things they find easy, but not the optimal things for improving their strength.

/end anecdote


Why is Qg4-Qe6 the correct move here? Given this board setup:

6k1/1p3rpp/1q1p4/p2Pp3/P5Q1/1P3PP1/2R3KP/8 w - - 3 13

Puzzle states: White to move, find the best move. The puzzle solution says Qg4-e6 and the rationale is that Rc2-c8+ cannot be stopped.  It seems to me, and some computer programs agree, that going directly for Rc2-c8+ is better because it forces a response of Qb6-d8 followed by Rc8xd8+ Rf7-f8, Qg4-e6+ Kg8-h8, Rd8xf8#. I am no master, I barely can call myself novice. So why is the solution saying that Qg4-e6 is better?

You're absolutely right. Qe6 only seems to draw:

6k1/1p3rpp/1q1p4/p2Pp3/P5Q1/1P3PP1/2R3KP/8 w - - 3 13

1. Qe6 g6 2. Rc8 Kg7

There's no forced win for white here as far as I can see.


Algebraic to coordinate notation converter I am building a chess board where I have one LED for each column and row, so I can represent moves by iluminating the orogin coordinate (e2) and the destination coordinate (e4)

However chess algebraic notation is simplified and the origin and destination coordinates need additional info to be calculated (like the board and the rules for each piece)

I am looking for some library or function that does this convertion (any language is fine).

Basically I need this function to translate my board coordinates to a chess engine notation and viceversa.

Java:  https://github.com/bhlangonijr/chesslib/tree/master/src/main/java/com/github/bhlangonijr/chesslib

C++:  https://github.com/alexmdc/chesslib

Python:  https://pypi.org/project/python-chess/

C:  https://sourceforge.net/projects/sankit/

These are all able to return long algebraic notation.  Stockfish is reported to also.


Was the value of thorn pawns fully appreciated in decades past? Many videos on YouTube channel "Kingscrusher" which discuss the play of new neural-net engines like Leela Chess Zero focus considerable attention upon the development of "thorn pawns" which are pawns that have reached the sixth rank and are blocked by a pawn in front but do not have pawns ahead of them to either side.  In my limited study of the game in decades past, I've seen great significance given to passed pawns, but never any special attention given to thorn pawns.  Do such pawns have a significance that has only been fully brought out as a result of AI-assisted research, or have they always been understood but simply not in things I'd read?  Or is Kingscrusher giving them more significance than they deserve?

A typical thorn-pawn situation would occur when Black has pawns at f7, g7, and h7, white moves h5, Black g6, and white pushes h6.  If Black has castled kingside, that pawn at h6 can be very hard to capture, and its presence kills the escape square at g7 and the possibility of easily establishing one at h7.  Was that a common pattern in years past, and if so what was it called?

I had never heard the term, but such pawns are very important for their contribution to certain mating patterns, the most famous of which would be Damiano's mate, which was included in Damiano's 1512 book Questo libro e da imparare giocare a scachi et de li partiti. Here's an archetypal example:

[FEN "5rk1/6pQ/6P1/8/8/8/8/8 w - - 1 1"]


Why can't a piece (that isn't a pawn) capture en passant? Why can't a piece (that isn't a pawn) capture en passant? When a pawn makes a two-square move, the en passant rule says that on the next move, any pawn that could have captured it on the single-advance square may do so.

So why doesn't the rule allow a non-pawn piece that could have captured it on the single-advance square to do the same? For instance, in the position

[fen "7k/8/8/8/2n5/8/P7/7K w - - 0 1"]

1.a4

why isn't the knight allowed to respond 1...Nxa3?

I believe the en passant rule is designed to cope with the fact that pawns do not move backwards, hence if the en passant rule did not exists you could have a lot of blocked positions, making play slower and probably more drawish.

Differently from pawns, pieces can move backwards, so the black Knight in your example still has the possibility to move backward and stop/capture the white a pawn. Therefore no need of allowing the en passant rule for pieces.

Said that, there is in a special case a sort of en passant like rule for pieces: castling is not allowed if an opponent's piece controls one of the squares that the King would go through while castling. You can see that as a sort of threat of hitting the King "en passant" during the castling move.

At a large extent chess rules are what they are because they resisted the test of time and made an interesting game. Same goes for pawn moves. The 2-step move from the pawn initial position did not exist either from the beginning, it was introduced later to make play faster and more dynamic; the en passant rule was likely introduced shortly afterwards to avoid large pawns blockades.


In Queen's Indian - Classical Line, why is ... Bb4+, Bd2 Be7 preferred over Be7 directly Consider the following line

[FEN ""]
1.d4 Nf6 2.c4 e6 3.Nf3 b6 4.g3 Ba6 5.b3 Bb4+ (5... Be7) 6.Bd2 Be7 (6... Bxd2+)

Black hardly ever plays 5... Be7 directly (I could only find one such game), but rather plays the above sequence (this sequence happens 1573 times).  The variation 6... Bxd2+ happens 54 times.

This suggests that it is better for black if white has the Bishop on d2.  But I cannot see why this is.

White's intended setup involves fianchettoing his dark-squared bishop on b2. The "free move" 6. Bd2 brings more harm than good:

Transferring the bishop onto the long diagonal, if white wishes to, will still take another move (i.e. Bd2-c3), but more importantly, if he does, the bishop on c3 takes away the square for the knight, which is preferred in many lines.
In many lines, white wants to play d5, aiming for a Benoni-like structure (which is bad for black in these cases); the bishop on d2 blocks the queen's defence of the d5 square, making this push harder to achieve.

For case 1: consider the "old" line, and compare this to a possible variation that arises after giving the check on move 5 instead:

[FEN ""]
1. d4 Nf6 2. c4 e6 3. Nf3 b6 4. g3 (4... Ba6 5. b3 Bb4+ 6. Bd2 Be7 7. Bg2 Bb7 8. O-O O-O 9. Nc3) Bb7 5. Bg2 Be7 6. O-O O-O 7. Nc3 Ne4 8. Qc2 Nxc3 9. Qxc3 f5 10. b3 Bf6 11. Bb2

Clearly, in this case, having the bishop on d2 is worse than having it on c1!

Long story short: the check disrupts white's set-up.


Is it possible to checkmate with knight and king against king? I would like to clarify two things:

Is it possible to checkmate with only a knight and a king against a lone king?
What will happen when one side has a king and knight and the other has just a king, does the game have to be drawn due to insufficient material?

If you drive an enemy king into a corner, you still need to control four different squares to checkmate him. Your king can control two of those squares (but cannot approach the enemy king), your knight can control the third, but there is no way of controlling the fourth. That is, it is impossible for the knight to control both the corner square and the one adjacent to the enemy king (the one your own king doesn't control).

So the result would be a draw -- insufficient material to win.


"Chess is 90% tactics" - should a player focus more on tactics in order to improve? The following quote has been attributed to many chess masters; "Chess is 90% tactics" - from Teichmann to Capablanca. It has also been said that 90% of the games are decided on tactics and tactics are the foundation of positional play. And many other similar statements.
My question is should a player commit 90% (or most) of their time on tactics as a recipe for improvement?

Although I agree that chess is 90% tactics when actually playing at the board, it really depends on where you are strenght-wise as to how much time you spend on tactics. By the way, when they use the word "tactics" there, I would say "tactics and calculation".

When you are beginning, I firmly believe that spending 90% of your time on tactics will be the best use of time, and you will get your biggest bang-for-the-buck time-wise. I once guided a 38-year-old from 1000 to 1850 on ICC in just three months by having him do 50 tactics problems per day, spending no more than two minutes per problem. He did nothing but tactics during that time, and play. I firmly believe in that immersion method of learning.

As you get stronger, let's say, 1800, you need to start spending more time learning about position. That will continue forever, but it becomes much more refined as you get stronger. You should still spend a lot of time doing tactics. I have found that even 2100 players are not that strong tactically, and even as a 2200+ for decades, I miss too much.

As you become a strong master, in particular GM, they need to work on openings more than any other group since so much is won at that level based on preparation.


Is there any website where I can play simultaneous chess against many opponents? This is purely for my fun (and also practice!), but is there any place online where I can play simultaneous chess against many opponents?

This would be against human players, of course, not against computers.

You could do that on FICS, here's how:

Simuls

  "Simuls" = simultaneous chess matches; playing more than one opponent at a
time.  It is possible to play more than one opponent simultaneously on the
chess server.  Below are sections for Starting a Simul and for Joining a
Simul.

  Users using an interface that only supports a single board (that is if
two games are being observed a move from the second game will cause the
position of the first game to disappear  (such as Winboard and Xboard)) should
issue "iset singleboard 1" before starting a simul.  This will ensure that
when simul participants move, only the board the simul holder is at will
update.

STARTING A SIMUL

  In order to play more than one chess match simultaneously you need to do the
following:

1. Start the simul with the "simstart" command.  Announce your simul
   conditions on shout and cshout enough to get the word out, but not so much
   as to annoy users.

2. Other users must then challenge you with "simmatch".

3. Accept or reject the challenges as they come in.  The first game will be
   colored as is if was an ordinary match.  The next game will be the
   opposite color, the next the opposite to that and so on.

4. When you are satisfied that you have started the number of games that you
   can handle, turn off your open flag with "set open 0".  You can see your
   games with "simgames".

5. You can then start making moves on the board.  The "simnext" command moves
   you to the next board; "simprev" moves you to the previous board.  You
   will focus on one game at a time, going in a particular order.  If you
   wish to skip to a board of particular interest "goboard <player>" or
   "goboard <game number>" will take you to that board.

6. If you are bothered by how long a player is taking to make the next move,
   or they are being disruptive you can abort that game with "simabort".  You
   can also force an adjournment with "simadjourn".  Only games adjourned
   during the simul can be resumed.  After the simul any outstanding simul
   games may be resumed as normal matches.  Should there be a need to
   terminate the simul "simallabort" and "simalladjourn" will abort or adjourn
   all games respectively.  Both commands will also terminate the simul.

7. When you are finished type "simend".  This will return you to normal
   playing mode and inform you of your statistics for the simul.

Various commands you can use while running a simul include:  goboard,
simabort, simadjourn, simallabort, simalladjourn, simnext, simprev and simend.

JOINING A SIMUL

  In order to play against a user who is open for playing simultaneous
matches, here is what you do:

1. Using the "simmatch" command, challenge the person you will be playing.

2. You will be informed when the simul player is coming to your board.  You
   should be prepared to move either before or shortly after that player
   arrives at your board.  If you do not move within a reasonable time
   period, your game could be aborted.

3. It is impolite to offer a draw unless that player is at your board.  It
   could very easily confuse the simul player if offers come in from
   different users at once.

OBSERVING A SIMUL

  You can observe all games in a simul once they have started by typing
"simobserve simul_player".  All of the simul_player's simul games will be
added to your observation list.  As the simul_player moves from board to
board, so will you.  When the last game has ended, you will see the final
results from the simul games.  You can also use the "follow" command for this
purpose.  Using the "observe" command, however, is not reliable for this
purpose.

Reference.

I don't know if it affects your rating, never tried it. Be careful what you wish for :)

There's also RedHotPawn, it says that  it offers that, maybe a member can verify that, I signed up there a year ago never used that site. But it's the second most popular online chess website after Chess.com I believe.

PlayChess server offers that as well but it's not free, but it's well known server, best of the best.

On Chess.com, you could play live chess and duplicate tabs, and you'll end up playing more than games at once, not the same window though.

There's also gameknot.com, I have never heard of it, but they claim it is possible to play such games on their site.


How should White continue after Nxb4 in the Evans Gambit? Recently I have been playing the Evans Gambit as many times as I can and for the most part, black plays 4...Bxb4, but someone played 4...Nxb4 and I wasn't sure how to continue.  After the following moves below, how should I continue with the Evans Gambit as white?

[FEN ""]
1. e4 e5
2. Nf3 Nc6
3. Bc4 Bc5
4. b4  Nxb4
5. c3  Nc6
6. d4  exd4

4...Nxb4 directly transposes to the main line with 4...Bxb4 5. c3 Bc5.

In that line, white usually plays 6. d4 exd4 7. O-O!.

Black cannot take the pawn on c3 because of 8. Bxf7+! Kxf7 9. Qd5+ picking off the bishop on c5 with an overwhelming advantage.

[FEN ""]
1. e4 e5 2. Nf3 Nc6 3. Bc4 Bc5 4. b4 Nxb4 (4... Bxb4 5. c3 Bc5) 5. c3 Nc6 6. d4 exd4 7. O-O $1 dxc3 $2 8. Bxf7+ $1 Kxf7 9. Qd5+


Rook+Knight Endgame-Play For Checkmate? I found myself in this position as Black during a recent endgame situation with White to move.
[FEN "8/7k/2R4p/2p3p1/2N2p2/P4PnP/1P2r1K1/8 w - - 4 43"]

What is a good way to approach checkmate from here? Is it impossible to force this with the rook and knight alone (with this position)? Or is it a better idea to start pawn play along the e to h files?

Some general advice about kings cut off on the 7th(or2nd) rank in rook endgames.
Involve your king or get your N to f3.
1.Kg1 Nf5!? {going after the f3 pawn.} 2.Rxc5 Nd4 (2...Kg6 also comes into consideration but
 is not tricky enough. although it is my personal fave) 3.Kf1! (3.Ne5?? Rxe5! -+) Rh2=

Involve a pawn!
1.Kg1 h5! {in order to get a pawn to h3 or f3 ASAP. Black will then threaten mate in two ways: ...Rg2# and ...h2#} 2.Rxc5 g4! -+

I have only used my head to give instructions. No computer, just to show what the general plans are. I'm IM but compared to a comp I'm nothing. So please forgive me if this is completely wrong. The general ideas are still valid though!


How can I improve my knowledge of pawn structure theory? What resources (books, videos, websites) are there to help me improve my understanding of pawn structures?

The old classical book by Hans Kmoch, Pawn Power in Chess is almost entiely devoted to this subject.

It is often used as a reference because of its numerous useful examples, but also mocked for the author's tendency to over-theorize every principle and forge neologisms that have not made their way, half a century later, into common chess vocabulary.

But as long as you don't mind skipping some sophisticated words like 'leucopenia' or 'melanoarchia', it remains an excellent ressource for studying pawn structures.


Why does Stockfish NNUE flatline? Flatline - to produce a flat evaluation curve.
As I understand engine chess, engines "flatline" in fortress positions. In these positions there are a lot of effectively-equivalent positions that return the same static eval. For example, in a KR vs KB endgame, almost all positions are the same, so it's not surprising that the eval flatlines.
NNUE however is different, because it's a neural network. It's hard for me to imagine that all the computations that's needed in a NN can yield exactly the same number for many different positions. That's why for example Leela Chess Zero never flatlines. How, then, can Stockfish NNUE flatline?
Example of a game where Stockfish NNUE flatlines: first from move 24 to 32 at 0.13, and then from move 33 to 38 at 0.05.

It seems this is happening because for endgame positions, Stockfish uses its handcrafted eval function. This is why Stockfish still has a contempt setting, since it's unclear how to implement contempt with NNUE eval, but contempt is still applicable whenever Stockfish uses its handcrafted eval. The handcrafted eval can flatline, therefore Stockfish can flatline as well.


What is the current highest rated chess engine? http://www.computerchess.org.uk/ccrl/4040/ - Indicates that it is Komodo 10 but I am not completely sure this is up to date.

CCRL has not tested Komodo 10.1 yet.

IPON has:  http://inwoba.de/

2016.07.23
Komodo 10.1 with a plus of 8 Elo in the full list and 11 Elo from one RRRL to the next.
This version would not be tested because it is to close to the last release but as it is the reigning world
champion it should be integrated.

1 Komodo 10.1    3253
   2 Stockfish 7   3228


In speed chess (especially bullet), are dirty tactics tolerated more? In bullet chess, well, it's frantic. And sometimes I find myself making dubious checks just to gain time. Or funny gambits. But it feels unbefitting of the royal game.

Is bullet chess bad for the overall chess community's reputation?

In my opinion chess and bullet chess are a kind of sport or competition. Everything what happens on the board is legitimate, if it is according to the rules. There is no such thing as an evil or devious move. You may play risky, repeat moves or do moves for "psychological" reasons. If the opponent thinks there is something wrong with that she or he needs to show it by playing better.

Sometimes player continue playing a drawn position, because their opponent runs out of time and they hope that the opponent will blunder. That is fine, since time is part of the game. Anand won a game against Gelfand in this way in last world championship


Kasparov quote on the simple math behind attacking I've seen several references to a certain Kasparov quote that paraphrase the idea of the quote without giving the actual text of the quote, or indicating where he said it.  The idea is something like "if you simply point more pieces at the enemy king than the enemy has positioned for defense, then a successful attack is almost assured".  Arithmetic is sometimes mentioned, in the sense that just having a greater number of pieces in a specific region of the board means you have the advantage in that region.  I'm looking for the exact quote, does the description ring any bells?
I notice multiple questions already about specific Kasparov quotes, probably in part because he's said and penned so many quotable things in his long career.  I've tried googling this one several different ways, but I've always come up empty.  It's not particularly easy to find one specific quote on how to attack, when Kasparov has written a great deal on world affairs, propaganda, and Vladimir Putin that turn up in the results if you search for Kasparov quotes on "attack".

Finder's credit goes to Akavall.  Kasparov's explanation of how he calculated an attack against Karpov appears to be the origin of the quote I've seen referenced.
youtube.com/watch?v=SMe-hvCwTRo


Which of the pawns in front of the king should be moved in order to prevent a back-rank mate? Assuming we're playing white and a bank rank mate is being threatened. Which one of the pawns (f, g, or h), in most cases, should be moved? Is there a general rule for this?

Of course, the concrete position is always more important than general "rules". However, as some guidelines of what is typically played:

f2-f3: Rarely. It opens up a dangerous diagonal (a7-g1) and usually also the second rank (normally, the d- and e- pawns were moved early on). Even if Black can't mate directly, they can often at least kick White's king around.
f2-f4: Occasionally, to immediately counter-attack a Black center position on e5 (if the second rank can be covered through other means).
g2-g3: Occasionally. Also opens up a diagonal (a8-h1), but that can be okay if Black has no queen and light-squared bishop anymore to exploit it and/or if White can play their own light-squared bishop to this diagonal.
g2-g4 or h2-h4: Occasionally. Can make sense to grab space when there are few pieces left (the pawns get vulnerable to piece attacks) or sometimes even to launch a counter-attack on Black's king.
h2-h3: Statistically, probably the most played among the pawn moves. It creates the  smallest weaknesses on paper - but as can be seen from the many alternatives, it's by far not a move that should be played in all positions. Especially not if Black controls h2 with another piece, obviously.
No pawn move at all: The better the player, the more likely they are to try and parry the threat without actually moving pawns. Usually, moving flank pawns to open up a vital escape square for your king doesn't do anything else on the board (especially when moving to only the third rank) and can thus be seen as a waste of tempo (on top of creating structural weaknesses). Sometimes, that's a sacrifice you just have to make to prevent mate, but if there is another way (covering the checking square with a piece, blocking the way, etc.), it's often to prefer.


How to convert ChessBase format files to .pgn? While downloading some games I came across some files in ChessBase format:

.cbv
.cbf
.cbh

I would like to know if is is possible to convert these files to .pgn format without using proprietary software and how it can be made.

Well since the protocols creating cbv, cbf and cbh formats are not made publicly available, one will certainly not find any such conversion tool (i.e. unclear how they are encoded to reverse them to pgn).

Other reason maybe that the difference between all these formats is just due to an "incremental encoding" that is being used, which means that for it to be possible to go backward, to a pgn format, only the chessbase engine can do so!

Until a way around this is found, you can use playchess free program or easier the chessbase light (which is free), where using

choose file->new database and create pgn files

will allow you to obtain pgn formats again.


Can this knight move level the game? As clearly black cannot trap the white queen for longer. So, won't Nxd4 be the best move in this scenario? Letting the queen escape and take a piece for his lost rook. Nxd4 will be followed by either Nxc2 or Nxe6. What are the different ways in which white can counter this move?

Q1bq3r/p1ppk1bp/1pn1B1pn/4PpN1/3P4/8/PPP2PPP/RNB1K2R b KQ - 0 1

1... Nxd4

This is a funny looking position, which I assume you probably reached out of a poorly played Dutch defense, something along the lines 1.d4 f5 2.Nf3 g6 3.Ng5 Bg7 4.e4 e6 5.Bc4 Nh6 6.Qf3 b6 7.Bxe6 Ke7 8.e5 and so on... (or 1.d4 f5 2.Nf3 g6 3.Ng5 Bg7 4.e4 e6 5.Bc4 Nh6 6.Qf3 b6 7.e5 Ke7 8.Qxa8 Nc6 9.Bxe6) which are very weird looking...

With little analysis I think you convince yourself that black is completely lost here and Nxd4 doesn't come to rescue either. Simply put, white is a clear piece up, the queen isn't really trapped, black's king is a mess, and there's just not any piece coordination to create any counter-play whatsoever. As pointed out by TMM in the comments after Nxd4 white just retreats the bishop to b3 and protects everything, this is the simplest and best move. Or even Bc4 to preserve the bishop and even provoke Nxc2+ which leads to some fun tactics either mating the black king or trapping the queen, for example:

Q1bq3r/p1ppk1bp/1pn1B1pn/4PpN1/3P4/8/PPP2PPP/RNB1K2R b KQ - 0 1

1... Nxd4 2.Bc4 Nxc2+ 3.Kd1 Nxa1 4.Nxh7 Ke8 (4...Nf7 5.Bxf7 Kxf7 6.Qd5+ Ke8 7.Bg5 ) 5.Bg5


Checkmate without check beforehand [Title "fucccommies-Diam0ndJake, chess.com, 7/8/2020"]
[FEN ""]

1. e4 e5 2. Nf3 Nf6 3. d4 Nc6 4. d5 Nd4 5. c3 Nxf3+ 6. Qxf3 Be7 7. Bb5 O-O 8. O-O c6 9. dxc6 bxc6 10. Bc4 d5 11. exd5 cxd5 12. Rd1 Qb6 13. Be3 Qb7 14. Bxd5 Nxd5 15. Rxd5 g6 16. Na3 Bxa3 17. bxa3 Qb2 18. Rad1 Qxa2 19. Ra5 Qb3 20. Rxe5 Bb7 21. Qf6 Qxd1#

In this game, I which my opponent and I played poorly, I ended up winning without a check at all before the checkmate. Can anyone help me understand when checkmates can happen without a check?

Assuming you are Black, you have checked your opponent - your Queen on d1 is putting his King on g1 in check (and checkmate).
Edit: assuming Rewan Demontay's reading of your question is correct, then there's no stipulation that you have to check your opponent before checkmate. You can see this in well-known short checkmates, e.g. Scholar's mate. 1. e4 e5 2. Bc4 Bc5 3. Qh5 Nf6?? 4. Qx7# is checkmate without checking first.


Chess principles for beginner I'm trying to put together a flyer of the golden rules in chess for kids that are absolute beginners. I noticed that they ran into the same trivial mistake that could be easy to fix with a simple switch, and I guess the flyer could help flipping it. Here is my list so far, kinda ranked by how important the principles are :

Practical :

I shall take my time on each move, at least a good 20 seconds
I shall pay attention to what’s my opponent last move and what is the intent
I shall make sure that neither I nor my opponent is giving away a piece
I shall keep my hand on my chin as long as I am not sure of what will be my next move
I shall never resign
A bad plan is better than no plan
I shall not reveal my intent orally to my opponent
I shall consider my opponent plays like a grandmaster
Do not focus on one sector of the board. View the whole board

In game :

In the opening, I shall deploy the knights, bishops, and then castle.
I shall not take out my queen in the opening
I shall use my king in the endgame
I shall connect my rook
I shall try to control the center
A knight on the rim is dim
Rooks smile on open files
When behind in material, I shall trade pawns. When ahead, trade pieces
I shall avoid doubled, isolated or backward pawns and try getting passed pawns instead
Whenever possible, I shall place my rook on the 7th or 8th rank
I shall double my rooks on the 7th rank

What do you guys think of it? Any other important principles I didn't think of? Feel free to use it.

Edit : Here's the final look of it. Feel free to use it !

The idea of giving your students some guidelines for playing good chess is good in principle, but we have to be aware of its limitations too. For the "practical" ones:

1 This is great until you play a 5-minute blitz game. You also don't often need 20 seconds in a capture-recapture sequence. This illustrates the main problem with trying to create fixed rules, they don't apply in every situation. I would go for "think until you make sure you are not blundering"
2, 3 and 4 are good pieces of advice!
5 is just bad etiquette. I understand what you mean but you should definitely resign if you are a queen and two rooks down in material
6 is pretty controversial. Just say "I shall find a good plan". Anyway beginner games are rarely decided on planning but on blunder exploitation
7, 8 and 9 sound fine to me.

The "in-game" principles are generally OK, but meaningless outside of their context, sometimes even false or contradictory with one another. If you are going to present them, please do so by providing good examples of how those rules actually apply.

As a final thought, please keep in mind that it's better to let your student figure out the "in-game" principles themselves rather than you showing them as if they were the Ten Commandments. Your mission should be to give them hints in their discovery, rather than being the word of Truth. For the sake of example, let's take in-game rule No. 6. I would review one of their games where they have an awful knight, then try to help them figuring out why the enemy's attack was so devastating. Eventually, they'll see how useful the knight would have been in an active square creating counterplay


How do I analyze my game after playing? What techniques do you use to analyze your games or other people's games?

How much time do you spend on analyzing the game?

Are there any tools (electronic or manual, such as a piece of paper) you use during analysis?

Analyzing your own games is the best and fastest way to improve in my opinion.

As soon as possible after the game, write down the variations that you were thinking about during the game, especially the ones that were not played.  This will be useful when you come back to the game after days, months, or even years.  As you improve, it will be helpful to see what you were thinking during the game.  That way, you can pinpoint how you can improve your thought process in future games.

When you start analyzing, use a chess board, but don't use an engine at first.  Look for moves where you made a mistake or missed something important.  If you lost material, go back and find the moment where you blundered.  If you got into a bad position, try to identify the moves that led to that position and evaluate some alternatives.  Put everything you come up with into your chess program/database (you are using some kind of a database, right?).

After you've gone over the game "by hand" (this should take at least half an hour for a slow game, even more time if it was a complicated position), now it's time to use a chess engine.  Go through all of the moves and take note of where the engine says that you either made a poor move or missed an opportunity for a better move.  Again, add variations to your database.  If it's not clear why something that the engine suggests is good, investigate it further.  Try out some lines and see what the engine says.

At this point, you have an awful lot of moves in front of you.  Now it's time to try to take away some lessons from the game.  Go back through the game again and decide what specific thing you could have done better.  Did you make a very poor positional move?  Did you blunder material?  Did you neglect development?  Did you put a piece on a bad square?  Asking questions like this will help you in future games during the game.

The last thing that you can do is to ask a stronger player for help.  Bring all of the information you have to the stronger player and then go through the game once more.  The stronger player can give you suggestions for how to think in certain positions.  Basically, a chess engine can tell you what the right move is, but a stronger player is often needed to tell you why a move is correct.

You should try to develop your own analysis style as well.  If you are a strong tactical player, try to go through the game without making moves on the board, just analyze in your head.  If you are good at endgames, switch colors and analyze where your opponent went astray in the endgame.  Hopefully analyzing games is fun and not a chore!

Additional thoughts

I didn't mention studying the opening moves because that is less important than finding the specific points in the game where you made a mistake.  After you have looked at the game as a whole, studying the opening can often help you as well.  The best way to do this is to look for grandmaster games in the same opening that was played.  Find out what moves are commonly played, and then go through some games of stronger players in order to find good, general plans for the opening.  Try to see where you varied from these plans and determine why you didn't do what the stronger player did.  This is much more important than memorizing moves (although you will probably find that you've memorized many variations just as a matter of course!).


Benoni Defence Theory and Ideas I have played the Benoni for a while, and I frequently play bad moves in the opening. How could I play the Benoni - Pawn Storm Variation safely?

You shouldn't give a fig about "variations". Players don't lose games in the opening because they're bad at this variation or that system, they lose short games because they're bad at tactics (and that's your experience, yeah?).
Forget the dumb names of things. Pawn Storm This, Big Attack That. You have to learn enough tactics first.


Is there a master list of FEN chess positions for advanced beginner/intermediate? I'm an advanced beginner.  I don't have internet access as much as I like to, so I'd much rather have a series of chess position FENs that I can put into some free chess engine and then try to play them myself offline.  I've tried getting those huge books with bunch of problems for beginners (like "mate in three") but they're heavy to carry around and also I'm still struggling with visualization so I like to have the computer nearby.  I've also tried to just play a game against those free chess engines but I find it very difficult to maintain my focus.  It's much easier to work 30 minutes on a problem or two, take a break, then do another couple, until it becomes easy enough to visualize.

The sort of problems I have in mind are like the one I just mentioned (mate in X number of moves) but also ones see on the popular chess websites, like being given a position and try to either gain material or checkmate or prevent opponent from doing so.  In short, not so much positional chess than tactical.

Appreciate suggestions.

Do you have a smartphone or tablet? The Chessok (formerly Convekta) people have ported a number of their training programs to Android (and I'm guessing iOS), and they are much cheaper than the PC versions ($8 vs $15-20). Search for chess king in one of the app stores. This includes things like CT-ART, Elementary Chess Tactics I & II, Chess Tactics for Beginners, and others.

A quick search on Google found this as well:

http://tacticstime.com/tactics-time-download-page/


Play chess online and get an offical Elo rank I played chess 30 years ago an now I am back in the arena. I have some spare time to train and play online. Could you please recommend me a good place to do so. A web interface without the need of any special clients would be great. Even greater would be the possibility to earn an official FIDE Elo ranking to see my progress.

There is one (and so far only one) place where you can get the official FIDE rating - the FIDE Online Arena. It however needs a client. A quick introduction is here and the arena is at http://arena.fide.com

I have not tried it so I cannot comment on how good the interface is but I assume it is good. The killer feature is that it calculates official FIDE rating, which is calculated the same way as the official rating for over the board play thus they are directly comparable. Even better they are linked - every time a new FIDE rating list for over the board play is published this rating is incorporated in the online rating (in other words games played over the boards count to the online rating too). It does not work the other way around.

A very little known fact so far is that FIDE has introduced new players titles, so called FIDE Titles for the Lower Rating Band. Official info here and some basic info here. You earn these titles for online play but the cool thing is that they are valid for life and you can use them in over the board play as well. As an example if you consistently keep your online rating above 2000 you will become an Arena Grand Master (AGM).

It is very likely, and I would bet on it, that in future all most popular online servers will offer calculating the official rating too. This may take some time though.


Suggestions for endgame study I'm an unrated player with some experience playing and studying various aspects of the game. If I had to give a subjective rating to myself, I would say 1000-1100. In all my quest for improvement, I have come across the suggestion, "Study end games first" multiple times, so I decided to start with that.

In the last three days I spent quality time understanding KP vs. K end game study. Was fortunate to stumble upon a very good wiki article, which very logically and completely explained the topic. Now I'm clear with the key squares, opposition, sixth rank, square of the pawn concepts in these studies. I have even effectively worked out several exercises on this topic to my own satisfaction.

That brings me to my current need. I would like to move ahead in logical phases, gradually adding more knowledge and experience to what I have already gathered, and without just jumping all over the place. So then, what would be the next rung of the logical ladder I should step on? What should I study next? And what study material could help me in an organized and phased manner of study?

Many thanks in advance.

I would recommend Silman's Complete Endgame Course which has a syllabus targeted by USCF rating as well as regular quizzes.


How do you know when a FEN position is legal? I am making a research on validating FEN positions, at first it is obvious the basics things to look for, such as checking if there are only two kings and making sure the rows or columns add up and those kinds of things. But what other checks should I do to completely make sure a FEN is legal?.

Here is a well organized list that should validate 99.99%+ of common positions:
Board:

There are exactly 8 ranks (rows).
The sum of the empty squares and pieces add to 8 for each rank (row).
There are no consecutive numbers for empty squares.

Kings:

See if there is exactly one w_king and one b_king.
Make sure kings are separated 1 square apart.

Checks:

Non-active color is not in check.
Active color is checked less than 3 times (triple check is impossible); in case of 2 that it is never pawn+(pawn, bishop, knight), bishop+bishop, knight+knight.

Pawns:

There are no more than 8 pawns from each color.
There aren't any pawns in first or last rank (row) since they're either in a wrong start position or they should have promoted.
In case of en passant square; see if it was legally created (e.g it must be on the x3 or x6 rank, there must be a pawn (from the correct color) in front of it, and the en passant square and the one behind it are empty).
Prevent having more promoted pieces than missing pawns (e.g extra_pieces = Math.max(0, num_queens-1) + Math.max(0, num_rooks-2) + Math.max(0, num_knights-2) + Math.max(0, num_bishops-2) and then extra_pieces <= (8-num_pawns)). A bit more processing-intensive is to count the light squared bishops and dark squared bishops separately, then do Math.max(0, num_lightsquared_bishops-1) and Math.max(0, num_darksquared_bishops-1). Another thing worth mentioning is that, whenever the extra_pieces is not 0, the other side must have less than 16 pieces because for a pawn to promote it needs to walk past another pawn in front and that can only happen if the pawn goes missing (taken or playing with a handicap) or the pawn shifts its file (column), in both cases decreasing the total of 16 pieces for the other side.
The pawn formation is possible to reach (e.g in case of multiple pawns in a single col, there must be enough enemy pieces missing to make that formation), here are some useful rules:

it is impossible to have more than 6 pawns in a single file (column) (because pawns can't exist in the first and last ranks).
the minimum number of enemy missing pieces to reach a multiple pawn in a single col B to G 2=1, 3=2, 4=4, 5=6, 6=9 ___ A and H 2=1, 3=3, 4=6, 5=10, 6=15, for example, if you see 5 pawns in A or H, the other player must be missing at least 10 pieces from his 15 captureable pieces.
if there are white pawns in a2 and a3, there can't legally be one in b2, and this idea can be further expanded to cover more possibilities.

Castling:

If the king or rooks are not in their starting position; the castling ability for that side is lost (in the case of king, both are lost).

Bishops:

Look for bishops in the first and last ranks (rows) trapped by pawns that haven't moved, for example:

a bishop (any color) trapped behind 3 pawns.
a bishop trapped behind 2 non-enemy pawns (not by enemy pawns because we can reach that position by underpromoting pawns, however if we check the number of pawns and extra_pieces we could determine if this case is possible or not).

Non-jumpers:

(Avoid this if you want to validate Fisher's Chess960) If there are non-jumpers enemy pieces in between the king and rook and there are still some pawns without moving; check if these enemy pieces could have legally gotten in there. Also, ask yourself: was the king or rook needed to move to generate that position? (if yes, we need to make sure the castling abilities reflect this).
If all 8 pawns are still in the starting position, all the non-jumpers must not have left their initial rank (also non-jumpers enemy pieces can't possibly have entered legally), there are other similar ideas, like if the white h-pawn moved once, the rooks should still be trapped inside the pawn formation, etc.

Half/Full move Clocks:

In case of an en passant square, the half move clock must equal to 0.
HalfMoves <= ((FullMoves-1)*2)+(if BlackToMove 1 else 0), the +1 or +0 depends on the side to move.
The HalfMoves must be x >= 0 and the FullMoves x >= 1.
If the HalfMove clock indicates that some reversible moves were played and you can't find any combination of reversible moves that could have produced this amount of Halfmoves (taking castling rights into account, forced moves, etc), example: a side with many pawns and a king with castling rights and a rook (the HalfMove clock should not have been able to increase for this side).

Other:

Make sure the FEN contains all the parts that are needed (e.g active color, castling ability, en passant square, etc).

Note: there is no need to make the 'players should not have more than 16 pieces' check because the points 'no more than 8 pawns' + 'prevent extra promoted pieces' + the 'exactly one king' should already cover this point.
Note2: these rules are intended to validate positions arising from the starting position of normal chess, some of the rules will invalidate some positions from Chess960 (exception if started from arrangement Nº518) and generated puzzles so avoid them to get a functional validator.


16 roses, 16x16 board; maximum double-attacked squares while all 256 squares are attacked at least once? The rose is a piece that is best described as a "circular nightrider", able to reach up to 32 other squares from the center of a 13x13 area by making consecutive knight jumps in a rotating fashion in a single move as long as no landing square en route is occupied. Incidentally, this rotating movement allows it to essentially pass a turn by returning to the square which it started its move from if it's completely unobstructed along at least 1 circle; though it obviously does not protect itself this way. I'll provide a diagram to illustrate its movement capabilities:

With 16 roses, including but still obstructed by squares occupied by other roses except the square occupied by an observed rose itself; what is the maximum number of squares on an otherwise clear 16x16 board that can be double-attacked while all 256 squares are attacked at least once each? For the purposes of this question, a square that is attacked 3 or more times does not count for anything more than a square that is attacked twice.

I feel I should note that I personally have yet to find an arrangement that attacks all 256 squares at least once by my own efforts; the very corners of the board in particular appear to require poor positioning in order to reach. However, seeing as 16 roses times 32 squares a single rose can theoretically attack creates a theoretical max of 512 attacks; I will be very surprised if an arrangement that meets the "attack each square at least once" prerequisite actually doesn't exist. If it should seem that this is the case, I would like an explanation as to why.

Sopel hasn't been around for a couple of years, but his solution is pretty and worth posting.

The pink squares contain the 16 roses. Each rose attacks all the squares whose distance away is sqrt(5), 4, 3 x sqrt(2), sqrt(29), 4 x sqrt(2) or 6. A rose does not attack the square it occupies.
All the squares are attacked from 1-3 times, including the squares which are actually occupied by the roses.
Addressing the original question: 100 squares are attacked more than once, of which just 8 are attacked three times.


Why is Tal talking about 10. Qf7 when 10.... N5f6 is possible? I am picking from the book "Attack with Mikhail Tal" Chapter 1, pg 6. Tal annotates the steps and his thought process on the Tal-Larsen 1965 match.
[FEN ""]

1. e4 Nf6 2. e5 Nd5 3. d4 d6 4. Nf3 dxe5 5. Nxe5 Nd7 6. Nxf7 Kxf7 7. Qh5+ Ke6 8. c4 N5f6

Tal continues with 9. d5+ Kd6 10 Qf7 Ne5. I am stuck on the Qf7. Why is Qf7 possible when there is 10... N5f6? What am I missing here?
Here is the original excerpt.

You made a mistake when transcribing move 7. It is 7. Qh5+, not 7. Qf3+. Move 10 is then Qh5f7, which is not blocked by the Nf6.
[FEN ""]

1. e4 Nf6 2. e5 Nd5 3. d4 d6 4. Nf3 dxe5 5. Nxe5 Nd7 6. Nxf7 Kxf7 7. Qh5+ Ke6 8. c4 N5f6 9. d5+ Kd6 10. Qf7 Ne5


Mutually agreeing to draw? I was involved in an endgame where it was my King against my opponents King, Knight, and Bishop and I knew he could checkmate me, but he wasn't aware how.  I just kept going in circles, dancing around his pieces and he could not figure out how to checkmate me.  Into move 140, I was getting frustrated and thought about either resigning or asking for a draw.  I eventually asked for a draw and he agreed, so my question is whether you are on the losing end or the winning end, when is it time to mutually agree to a draw?

When to mutually agree a draw depends on the skill level and the position in question. An agreed draw is most logical when neither side believes they have real winning chances (Sometimes people just chicken out in complex positions...). In the case you describe, practically speaking, there are no real winning chances for either side. Alternatively, 2 GMs may rightly agree a draw in many drawn theoretical endgames where mortals such as you and I should probably play on.

For the rulebook perspective... the rules state that "The game is drawn upon agreement between the two players. This immediately ends the game." It is correct to offer the draw after making the move but before pressing the clock. You and your opponent may agree to a draw at any time. In terms of etiquette, it is generally considered poor practice to offer a draw when losing or significantly worse. It is also poor etiquette to repeat draw offers and the TD may penalize you for "annoying the opponent".  As a matter of preference, I offer a draw only when I believe that I have no real chance of losing. Rules such as 3 move repetition and the 50 move rule are there to ensure that your opponent cannot meaninglessly torture you in a position such as the one you describe.

In your given situation, it may be useful to claim a draw by the fifty move rule. The fifty move rule states: "The game is drawn when the player on move claims a draw and demonstrates that the last 50 consecutive moves have been made by each side without any capture or pawn move." The case of B and N versus King is a classic example where 50 moves may elapse without a pawn move or capture.


Effectiveness of a spaced repetition system (SRS) for memorizing tactical patterns for long-term skill gain? After reading Micheal de Maza's article 400 Points in 400 Days and the paper Training in Chess: A Scientific Approach by Gobet and Jansen,
I have come to the conclusion that effective gains in chess skill for players below the A-class rating (<1900) must come from an equal gain in tactical ability. This is pretty well known in the chess community, and most people, when asked how to improve, will point to tactics.

Once we accept this idea of tactics being the foundation of amateur (<1900) improvement, it becomes a simple matter of methods, results and efficiency. In this regard, most chess players will look to books and websites which offer "chess puzzles". Some of the more popular websites, CTS (Chess Tactics Server) and ChessTempo, offer random puzzles, ordered by difficulty. Having used these websites for the better part of two years, one of the main problems I've found is the loss of "sharpness" or "board vision" when the regularity of puzzle reviews are interrupted. Often, even a gap of 1 week can severely cripple any progress made in tactical ability, so that constant daily practice is needed to maintain any growth.

Then I read about Micheal de Maza (from an article by Dan Heisman) and his method to increase 400+ rating points in a little more than a year. The crux of his method is what he calls "the seven circles" where he does 7 passes through a chess puzzle book, at which point he can solve the puzzles near instantly. In other words, he has memorized the puzzles and their solutions by sight.

Now it is my opinion that the book he chose to "memorize" (Chess Manual of Combinations) had a greater contribution than his actual method (the method is very inefficient, as I will discuss later) but I also believe that the memorization component was essential to sustained (i.e permanent) chess growth. Looking through the Chess Manual of Combinations, I can see that it follows many of the principles laid out in the second paper (especially regarding the building up of positions from the simple to the complex to create an internal hierarchy); it is also ordered by theme and difficulty.

But the question remains, what is the most efficient way to memorize this material? Certainly, doing seven passes through the book seems to be the most inefficient way (brute force usually is).

I am a big fan of spaced repetition software such as Anki, and I think that this software can be combined with the memorization method to yield some significant results, but before I begin such an undertaking I wanted to ask if anyone has already tried a similar approach (if not spaced repetition, at least the memorization of puzzles) and what results they obtained (particularly if it was quantitative, i.e changes in ratings).

Also, I have "Anki-ed" the Manual of Chess Combinations (Volume 1a only, 2a is in the works) and am wondering if anyone else is willing to experiment with this method along with me.

It is just anecdotal, and correlation is not the same as causation, but a few years ago I started using the Mnemosyne spaced repetition program to memorize

Opening lines (a few thousand cards here alone)
Positions from

Yusupov, Build Up Your Chess et al
Hellsten, Mastering Chess Strategy
Ivashchenko, Manual of Chess Combinations
Rosen, Chess Endgame Training
My own games where I had made a bad decision

During this time, my USCF rating, which had never moved much as an adult, went from under 1800 to over 2000.


Is there any published research into the Mighty Thor gambit against the French Defense? Are there any annotations on the obscure Mighty Thor Gambit?

[FEN ""]
1.e4 e6 2.a3 d5 3.e5 c5 4.b4

(which is different from The Wing Gambit:)

[FEN ""]
1.e4 e6 2.Nf3 d5 3.e5 c5 4.b4

At a tournament where it was played numerous players referred to it as "The Mighty Thor Gambit" but I've not seen that mentioned anywhere online.

I am not aware of any published analysis nor commented games in this line.

Note that Black can almost forcefully transpose into a 'regular' wing gambit with 4...Nc6 5.Nf3 [5.f4, 5.bc5, and 5.Bb2 cb4 all look worse] cb4.

In case he is looking for more original play, 4...d4, 4/5...Qb6, 4/5...Qc7 all look interesting and try to demonstrate that a3 might not be the most useful move for White when Black refrains from taking on b4.


Reasoning for Rook sacrifice [fen "rn1qk1nr/pp4p1/2p2p2/4P2p/1bp5/2NbPPP1/PP2N1BP/R1BQ1RK1 w kq - 1 11"]

Komodo 8 and Stockfish agree on Nf4 here for white ( sacrificing the rook for development). It does not however show Bxf1 next for black but instead fxe5 and then Nxd3. Why shouldn't black just take the rook instead of fxe5. I get that after white swaps queens black will not be able to castle but wouldn't this still be worth it materially?

Also keep in mind that the rook isn't necessarily being sacrificed free and clear, because taking back on f1 is a possibility (if not playing Ne6+ right away), meaning white is only sacrificing the exchange, while trading queens and leaving the black king exposed and vulnerable and unable to castle, so it's not as costly.


Did predecessors of modern chess use dice to determine which piece to move? According to the Wikipedia article of Magic: The Gathering, creator Dr. Richard Garfield has compared the evolution of the game from luck to skill as being similar to that of chess.

  According to Dr. Garfield, Magic has and would likely continue decreasing its degree of luck as the game matured. The "Mulligan rule", as well as card design, past vs. present, are good examples of this trend. He feels that this is a universal trend for maturing games. Dr. Garfield explained using chess as an example, that unlike modern chess, in predecessors, players would use dice to determine which chess piece to move.

However, the article on Chess doesn't mention dice in its history. Did predecessors to modern chess indeed use dice? And if so, was it removed as part of a maturation of design to emphasize skill over luck, as Dr. Garfield  suggests?

Richard Eales addresses this question in Chess: The History of a Game (p.30):

  On one last matter, whether or not the early Indian chess was played
  with dice, there is simply no evidence on which to base a general
  conclusion. Al-Biruni saw dice being used in the four-handed game
  (throw two to move the chariot, three for the horse, and so on), but
  this is a practice which continually crops up in the history of
  pre-modern chess, particularly when gambling was involved. The
  Chatrang-namak described chatrang as a game of pure skill but the dice were not unknown in Islam, and certainly reappeared more
  frequently in medieval Europe. There is no clue preserved in the
  structure of the game to betray whether the 'original' chess was
  played with dice or not.

So it seems that this question is one on which we should remain agnostic.


Are blindfold players allowed to look at the list of moves? I just read that Alexander Alekhine simultaneously played 26 blindfold games.

Are blindfold players allowed to look at the list of moves? Can they re-create the position in their mind from the list of moves, or do they have to memorize the position on each table?

They memorize the position on each table; In this kind of event, they simply don't have the time to spend to much time on each position. Also trying to re-create the position like this is not practical when you play blindfold chess

If you want to know (almost) everything on blindfold play, check out this great book on
http://www.blindfoldchess.net/

Cheers!


Are there mobile chess tutoring/training apps for Android or iPhone? I'm looking for a Chess tutoring/teaching app that I can dip in and out of on my phone. At the moment I use Shredder Chess to practice when on the move (which basically involves repeating the puzzles over and over) but I was looking for some sort of app which has structured lessons on openings, defenses etc. and explains the positions in depth like Chess Mentor does.

Does anyone know if this type of app exists?

Here are my Chess apps for Android:

iChess — lots of chess tactics to solve, all offline. You can also load your own PGN or purchase recent tactics based on openings, or from recent games.

Chess Book Study — a very innovative app that shows a board and an eBook in the same screen. It makes it easy to study chess books. You can even dictate and the moves are made on the board.

Analyze This — analyze a position with two engines, simultaneously!


Availability of AlphaZero and A. Grischuk's idea in the Anti-Moscow Gambit vs L. Ding I was watching some Fide Candidates post play conference and Grischuk mentioned that a certain move was suggested by AlphaZero. So I was googling a little and have a stupid question. Where is AlphaZero? I thought it is non-public and no-access engine and I really cannot find anything but an implementation of the algorithm on github based on their published paper but from the page it seems it is not really the AlphaZero.

So does anyone have more insight if AlphaZero engine is somewhere available to use or even play against? How would Alexander Grischuk have access to it?

No, as far as I know DeepMind's AlphaZero chess program has not been publicly released in any form, and I don't know if they plan to do so at any point. The only games of AlphaZero vs Stockfish that have been publicly showcased are the 10 games that can be found either in their pre-print paper, on their website or the chess news outlets such as chess24.

I guess the comment you're referring to is the one made during the press conference by Alexander Grischuk after his first game vs Liren Ding, where they played the Anti-Moscow variation of the semi-Slav Defense, an opening that has not occurred in any of the published sample games of AlphaZero vs Stockfish. So for all we know, as ETD has also pointed out in comments, Grishuk is jokingly labeling probably his 16.a4 novelty (or possibly the whole sacrificial variation after Nxf7) as an idea liked by AlphaZero but disliked by Stockfish. This is also pointed out in the chess24 report of the 4th round.

Grischuk essayed 16.a4 in this variation where the main move is usually 16.Bg4 (which became famous after the Topalov vs Kramnik game in 2008):

 [title "Semi-Slav Defense: Anti-Moscow variation 16.a4"]
 [fen ""]
 [StartPly "38"]

 1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 c6 5. Bg5 h6 6. Bh4 dxc4 7. e4 g5 8. Bg3 b5 9. Be2 Bb7 10. O-O Nbd7 11. Ne5 Bg7 12. Nxf7 Kxf7 13. e5 Nd5 14. Ne4 Qb6 15. Nd6+ Ke7 16. a4 (16. Bg4)


Could a chess engine do retro analysis? If I took a legal chess position, to what extent could an engine work out the previous moves? [in some other board games such as Othello such game reconstruction is done easily with an engine.]

Engines like Stockfish and Komodo are not able to work out the previous moves, because that is not what they are programmed for.

However, it is vanishingly unlikely that anybody can ever program an engine that works out legal previous moves. The logic of working out whether a possible previous move is legal or not is extremely difficult.

To start with, how do we list possible previous moves?

Possible previous moves, called retractions (if we ignore legality for a second) are easily found algorithmically - every piece retracts as it moves in forward chess (except pawns), and they could also "uncapture" an enemy unit - pawn, knight, bishop, rook or queen. e.g. wBc4 takes pawn on f7 in reverse looks like the bishop moving from f7 to c4, with a black pawn appearing on f7.

Pawns move 1 square backwards, and uncapture one square diagonally backwards. (You can figure out what the double step looks like.)

With regard to checks, one can retract into what looks like "check" in regular chess, and one must always retract to never leave the opponent in "check". (So if the previous example of wBc4xbPf7 checks the black king on e8, it required white to retract the bishop to remove the "check".)

Uncastling is easy to visualise (and adds the constraint that the king or rook cannot retract again). Un-en-passant is hard to describe and forms the basis of many classic retro problems. Unpromotion is again easy to visualise.

So listing all potential retractions is not difficult, from a programming standpoint. The incredibly difficult part is determining which retractions are legal. There are many reasons why a retraction cannot be legal, ranging from simple (retracting an uncapture to leave 9 black pawns on the board, for instance) to highly convoluted (cf. most retrograde analysis problems, see the Retro corner.)

See for instance this problem by Troitsky on Chess.SE, and my accompanying answer to it. A lot of logic goes into proving that there is in fact only one legal retraction by black, and this is not obvious, involving counting pawn captures, considering their order, and tempo constraints.

To write an engine to perform such a task, one must be able to elucidate the human logic behind it in such a way that a computer can execute the logic. This simply does not seem possible at all, given that "legality of retractions" is far more nebulous than "legality of forward chess moves".


Traxler Counterattack I've had a few looks at the Traxler counterattack before. It seems fine for Black, but somehow the engine (Stockfish) says that White has a +2.57 advantage after Nxf7, but not much advantage after Bxf7+. Why is this so, when this opening is accepted by masters?

I can't find it now, but I remember reading this exchange on Chessbase. A player just played ...e6 on one move, and then ...e5 on the next, seemingly losing a tempo for no reason. It was clearly computer preparation however. An interviewer asked GM Viswanathan Anand what he thought about the moves. Anand replied that if the computer thinks it's fine, then it's fine. Instead you have to analyze the lines afterwards to see why it's fine.
In other words: these days computers are so strong that their judgement trumps human judgement, including those made by world champion-caliber players.
Now the fact is that computers don't like the Traxler, even at high depth. It was played in the TCEC S17 superfinal between Leela and Stockfish. Here's the first game, and here's the reverse. Note:

These engines are playing on super hardware and achieve speeds and depths that would take very long for ordinary machines. When Leela played her fifth move, she was at depth 22/62. When Stockfish played its fifth move, it was at depth 43/62.
Both finalists thought 5.Bxf7+ is the best move.
Both finalists evaluated the position after 5.Bxf7+ as +1.5 for White (more precisely, Stockfish gave +1.5 for White; Leela thought White had a 60% chance to win).
Comparatively, in the starting position, White has roughly a +0.5 advantage.
There is some fluctuation in engine eval, so e.g. if Stockfish thinks a move that is +0.1 pawns better than the next-best move, the next-best move might still be playable. However, +1 is a pretty large gap.

Therefore the only conclusion here is that the human masters are wrong. The Traxler is objectively dubious at best. Playing this can work against humans because humans cannot find a string of "only moves" in a row to hold a position, plus it's psychologically difficult to defend against a strong attack for a long time. That's why humans - even top-level humans- often crack under pressure. The Traxler also offers plenty of opportunities for both sides, which is great if you want to play for a win and/or you think you are better than your opponent. But if you play the Traxler as Black in correspondence chess, you are asking for trouble. Maybe 32-piece tablebases will show that your position isn't lost, but you would have to fight hard for equality.
Finally I'll add that it's misleading to say the Traxler is well-regarded by masters:

Wikipedia's article on the Two Knights includes this quote: "No grandmasters have regularly adopted the Wilkes-Barre as Black, but Alexander Beliavsky and Alexei Shirov have played it occasionally even in top competition"
Chess Openings Explorer gives by far the most common response to 4.Ng5 as 4...d5 (which is also the main line of the Two Knights).

I'd call the Traxler playable in human games, but only as an occasional weapon.


White's Response to the Norwegian Defense In the Norwegian Defense of the Ruy Lopez

[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 b5 5. Bb3 Na5 6. O-O (6. d4 exd4 7. Nxd4 c5? 8. Bd5!)

Neil MacDonald suggests 6. O-O as a response. Why isn't 6. d4 suggested in the book?

Edit: 6... exd4 7. Nxd4 c5? does not work because of 8. Bd5! when White enjoys a comfortable lead in development. I ask what are the repercussions behind playing 6. d4 possibly followed by 7. O-O. Is this variation sharper?

The author suggested 6. O-O as a solid choice compared to the sharper 6. d4, but I don't see what's so sharp about it. White is simply challenging Black in the center. I guess it gives less information away about the central pawn structure. Is that the answer?

If you choose 6.d4 you must consider it either as a gambit or as a prelude to a queen sortie, since after 6...exd4 7.Nxd4?! Bb7 [not 7...c5? 8.Bd5!] 8.Nc3? c5! followed by c4 traps the Bb3.

7.Qxd4 is possible, but after 7...Bb7 you have to take 8...c5 into account again. (the immediate 7...c5? doesn't work because of 8.Qd5.) White queen will probably lose some tempi, and in the long run the open center may favour Black's bishop pair. For instance, 8.0-0 c5 9.Qe5+ Qe7 10.Qxe7 Nxe7 (10...Bxe7 12.Bd5!?) looks like Black is grabbing a pawn.

[fen "r1bqkbnr/2pp1ppp/p7/np2p3/4P3/1B3N2/PPPP1PPP/RNBQK2R w KQkq - 0 1"]

1. d4 exd4 2. Nxd4?! (2. Qxd4 Bb7 (2...c5? 3. Qd5) 3.O-O c5 4.Qe5+ Qe7 5.Qxe7 Nxe7 (5...Bxe7 6.Bd5!?)) Bb7 (2...c5? 3. Bd5!) 3. Nc3? c5! 4. null c4

In case of 8.O-O, 8.c3 or other moves, you would have to demonstrate what the idea behind the gambit is.


Should white be able to win this endgame? Should white be able to win from the position

[fen "8/5k2/3p1p2/3PnP2/1KP1r1P1/8/3RB3/8 b - - 0 67"]

with black to move?

(A game I was playing ended there when black just let

black's time run out due to having very little of it left.)

Black can take the g4 pawn, but Stockfish evaluates that as being much worse than

black's alternatives, regardless of whether the capture is immediate or after Ke7 Kb5.

Thus, play should presumably continue Ke7 Kb5 Nd7, resulting in the position

[fen "8/3nk3/3p1p2/1K1P1P2/2P1r1P1/8/3RB3/8 b - - 0 69"]

with white to move.  From that position, Bd1 is the only way Stockfish sees to make progress.

However, after Bd1, Stockfish thinks black should play Ne5, and then the line it gives is

4. c5 dxc5  5. d6+ Kd7  6. Kxc5 Nf7  7. Bc2 Re5+  8. Rd5 Rxd5+  9. Kxd5 Nxd6   ,

which results in a draw since

with white's pawn still on g4, Nf7 will establish a fortress because black can play Ke7 and N(x)g5 and even if white gives up the g4 pawn, white's king can't attack more than one of {h3,e4,h7}

and the only way for the bishop to do that is from g2, which leaves f7 safe for the knight

and

g5 fxg5 gives a tablebase draw, regardless of whether white plays that immediately

or after Ba4+ Ke7, and Ba4+ Ke7 Be8 Nxe8 gives a tablebase win for black
.

(Reminder:  My question was at the top of this post.)

White's main threat is c5, which forces a pawn exchange and a passed pawn with king covering queening squares. The bishop is covering the g pawn.

Should black force an exchange of that pawn, white's rook could go to e5 and capture the d pawn, allowing a double passed pawn.

If black defends c5, white first move his king to b4 to cover the next 2 pawn squares, then force black to zugzuang(by moving rook to a file) which forces black to stop defending c5 or move the rook.

If black moves rook to e5, putting pressure on the bishop, white pins black's knight and therefore forces a minor piece exchange, with a more active king, which will then go on and promote pawns.

If black stops pressuring the bishop, the endgame should be easily winnable.

As for Ke7, idea would be the same

For moves that does not either pressurise c5 or protects d6, force an exchange on c5 and you can win easily


Ways to notice opponent's threats during one's own move I am currently playing in a tournament and my last game was a total disaster. Without going into details, I missed a two-move threat my opponent had in the position (I'd expect a ~1600 Elo rated player to find this threat during a game) straight out of the opening and my position was practically hopeless afterwards.

However, after some time spent on self-pity I started reflecting on the nature of my blunder and I started to realize that this is a type of blunder I've lost countless games to. In this game, the following happened:

I was having trouble finding a good plan out of the opening, and before making the losing blunder I spent around 30 minutes on the clock.
The move I played should have been easily recognizable as a blunder for a player of my strength (~2200 Elo at the moment).
I noticed the threat almost immediately after pressing the clock, long before my opponent actually played the winning move (naturally he was a bit suspicious that someone like me would miss something THAT obvious; I could even see him throwing some suspicious glances, seeming like he wanted to ask me: "Are you for real!?").

After realizing that this was not an isolated event for me, I started to wonder: is this actually common for players rated, say, 2100+ Elo? Also, does anyone have any advice how to counteract this self-destructive psychological issue? Right now I'm at a loss for how to deal with it.

I am not 2000+ rated, but I experience this myself from time to time (I actually got better).
Reasons I found why I do this:

Being to excited about my plan, e.g. I see a nice tactic, which my opponent might not see, he plays a move which does not prevent it (apart from his threat).
"I am winning feeling", I get this when I won previous games against someone and am in a winning position again. Sometimes (especially when tired) I start to "just play it down". Then I start missing things like a Zwischenzug.

For countermeassures:

I focus more on opponents threats during his time, while developing my plans during my time. If he plays an unexpected move, I take my time. This way, I am constantly up to date about my opponents threats and I distribute enough time to think about his plans. If he plays really fast, I have to spend some of my time. Since I am used to spend more time for his plans, I do this quite automatically.
If I am feeling happy about a position, I tell myself, "Nice position, lets focus and find the closing moves". This helps me to focus (again).


How should black play to save this endgame? Recently I've played a game (with blacks) which ended with this position (White to move) :

[fen "3rk3/p1R2ppp/2p5/8/P1K5/8/1P3PPP/8 w - - 0 1"]

It's clear that White player can't protect his pawns in the second row, but the problem here is with the a file, should black protect his pawns in the a file, which will quite restrict his possibilities ?
Otherwise, Is it possible to just abandon this pawn, and go for white pawns in the 2nd raw ?
But the problem here is surely with the white pawn in a4 which is pretty advanced compared to black pawns.

How should black play in order to save his game ( a draw at least ?!)

This endgame is lost for black, but the best plan here is for black to enter 2nd rank and try to gain some pawns and throw some checks. White's plan on the other side is just to take a7 pawn and advance his a4 pawn till promotion

Good luck trying to SAVE that one


What is the least number of knights needed to cover the entire board? I’ve seen the solutions to the lowest amount of queens, bishops, and rooks are needed to cover an entire board, as in they can attack all squares and are the only type of piece on the board. What is the solution for this with knights?

Depending on whether occupied squares need to be covered as well, the number is:

[Title " 12 knights, Without Covering Occupied Squares"]
[FEN "8/5N2/1NN1NN2/2N5/5N2/2NN1NN1/2N5/8 w - - 0 1"]

[Title " 14 knights, With Covering Occupied Squares"]
[FEN "8/2N1NN2/2N1N3/2N3N1/2N1N3/1NN1NNN1/8/8 w - - 0 1"]

Problems like this are called domination problems and solutions for knights and other pieces as well as a reference are given on the wikipedia page on mathematical chess problems


What is the worst possible first move for White: 1.f3 or 1.g4? After making my engines evaluate the starting position for more than 10 hours each, here is what I got:

.

Fritz 12:

Depth = 25/65

Time = 10 hours and 30 minutes

1.f3 : -0.90
1.g4 : -0.77
1.Nh3 : -0.56
1.Na3 : -0.52
1.h4 : -0.47
1.b4 : -0.47
1.a4 : -0.42

All 13 other moves are -0.25 or more.

.

Houdini 3 Pro x64

Depth = 29/76

Time = 11 hours and 45 minutes

1.g4 : -0.51
1.f3 : -0.50
1.Nh3 : -0.38
1.Na3 : -0.37
1.h4 : -0.25
1.b4 : -0.20
1.a4 : -0.17

All 13 other moves are -0.12 or more.

.

One thing seems very probable: the worst possible first move is either 1.f3 or 1.g4.

So between these two moves: which is the number #1 worst possible move?

What is the worst possible first move for White: 1.f3 or 1.g4?

f3 doesn't contribute to the piece development ( it actually hinders it by taking away the best square for the Ng1 ), it doesn't fight for the center ( it only strengthens the e4 square that White can claim anyway with 1.Nc3 or 1.e4 ) and above all it exposes the king.

g4 vacates g2 for the Bf1 ( fianchettoed bishop is usually good ), it helps in the fight for the center indirectly ( you can weaken Black's control of d5 and e4 if Black plays ...Nf6 at some point, by simply playing g5 ) and pawn at g4 can be useful in kingside attack if Black castles short. It does weaken f4 and h4, so it is somewhat dubious, but it is playable ( although I doubt White can reach full equality...).

Therefore, when we compare the above facts, we can see that 1.f3 is clearly the worst first move, based on the opening theory ( since only one move is played it is to early to make final conclusions, since White may transpose into decent position with his next moves ).


When and why was the notation changed from descriptive to algebraic? When I was young I used to play chess with the the old form of notation KB (King Bishop square number), even books used to have the same notation, then later found that everyone was using algebraic, is descriptive notation dead? Why?

Though the previous answers have made some solid points, I think they have not yet given the main reason why algebraic notation has generally come to be preferred over descriptive notation: it is more absolute, less relative, than descriptive notation. What I mean is just this: in algebraic notation each square on the chessboard receives only one name, while in descriptive notation each square receives a different name depending on whether a move by white is being notated or a move by black. This alone makes algebraic notation more transparent, because things aren't relative to which side is on the move.

Consider, say, the g4 square (in algebraic notation). When white moves a piece there, descriptive notation says it is headed to KN4. But if black is moving a piece there, it is headed to KN5. There is just no need to have two names for this square, and it serves only to sow possible confusion in a way that algebraic notation does not.


How can an Elo 1300 player improve his or her endgame? I have noticed that, among opponents of Elo strength about 1300 (USCF class C to D), many play the opening and midgame almost as well as a 1400- to 1500-strong player but seem suddenly to drop to, say, 1100 strength as the endgame approaches. The 1300-strong player who blunders away endgame after endgame is a familiar character in the world of chess.

Without an excessive investment of the player's time, what are some ways a typical 1300-strong player can improve his or her endgame?

Some advices:

Look at grandmasters' endgames with comments.

Replay their games and try to understand their moves and the evaluation of commentators. There are several good books, I think Evgenny Shereshevsky's excellent classic "Strategy in the Endgame" is understandable at 1300-level. At least most of it, and you can keep the most difficult examples for later when you will have developed a better understanding of general principles. Some books about Bobby Fischer's endgames have been well commented too. I suppose there are good videos/DVDs on the market as well. Avoid anything overly complicated right now, like John Nunn's works; Mark Dvoretsky's and Karsten Muller's ones are very good but too hard at 1300 elo - keep them for later.

Start with pawn endgames.

The rules there are somewhat more clear-cut (there is basically one single goal: queening one of your pawns first), and they are mandatory if you want to understand more complex endgames later on, because several concepts are similar and because they may transpose to pawn endgames in case of exchanges.

Do not try to swallow too much theory.

Endgame theory can be surprisingly complex, it is a dry matter to memorize, and pratical endgames is what you should be looking for. At 1300 elo, I assume you already master the basic mates KQK, KRK and KBBK. KBNK is fun to look at but not super useful in practice, learn it if you enjoy it but don't force yourself if you don't.

I would still encourage you to learn KPK well enough to be able to evaluate any position with KPK in less than thirty seconds, and be sure about the next best move. Have a look at KPKP theory (counting in pawn races, opposition, trebuchet) and at KRPKR (Philidor, Lucena), but already here you merely want to get familiar with the ideas, not to remember everything.

Some training websites

like chesstempo or lichess offer endgame exercices and adapt their difficulty to your performances in solving them. If you have fun doing some once in a while (I sure do), do it! Usually the free registration is enough to get access to five or ten exercices per day - just the right amount for effective training !

Stay away from tablebases (and more generally from chess engines).

You may use them to have a look at the evaluation of a given position if you have already studied it by yourself or with a book/video and want to check your conclusions. But going through variations generated by tablebases is disheartening enough : sometimes they lack logic, or make you feel that simple things are overly complicated because they try to minimize distance to mate, and they come without explanations (or explanations limited to even more complicated variations)...

If you play endgames in your own games, study them afterwards.

The best way is: first alone or with your opponent, then write down your main conclusions/interrogations, and then review the endgame with a stronger player / a coach / a reference book if the position is a theoretical one / a software if really you have nothing better available. Finally, compare with your first notes, that's when you will make huge progress about your thinking process !

Good luck !


Equation for Handicap Are there any sort of equations for how much of a handicap one should receive to make a game between two players with differing Elo ratings as balanced as possible?

There might be a time equation to determine how much more time one player should receive in relation to the other. Or, an equation to determine how many more points one player should be up in relation to the other at the start of the game. Or, an equation that factors in both a time and point handicap. (When I refer to points, I am not referring to Elo. Rather, I am referring to point difference given from an engine analysis.)

If there's some way to translate point difference towards probability of winning then making a point handicap equation should be fairly easy, since one can figure out the probability of winning given the Elos of the players.

(I realize there are questions similar to this question. I have seen those questions, and they were not asking for the specifics that I am asking for.)

Are there any sort of equations for how much of a handicap one should
  receive to make a game between two players with differing Elo ratings
  as balanced as possible?

The short answer is "No", there is no scientific equation, but it doesn't stop people from trying.

For instance, our club runs an annual handicap tournament in which it tries to produce a practical answer to this question. The rules for the tournament are here.

  Players are first put into numbered bands according to their grading
  with the highest graded players in band 1 and lower graded players in
  bands 2 and upwards. Then the handicap when two players meet is
  determined from the following table according to the difference
  between the players’ bands.

  0 – no handicap, first named player in the draw has white
  1 – colour, player in the higher band number has white
  2 – 2 moves, player in the higher band number has white and makes two moves instead of one to start the game
  3 – f pawn and move, player in the higher band number has white, remove f7 pawn
  4 – f pawn and 2 moves, remove f7 pawn, player in the higher band number has white and makes two moves instead of one to start the game
  5 – knight, remove b1 knight, player in the lower band number has white
  6 – rook, remove a1 rook, player in the lower band number has white
  7 – queen, remove d1 queen, player in the lower band number has white
  8 – queen and knight, remove b1 knight, remove d1 queen, player in the lower band number has white
  9 – queen and rook, remove a1 rook, remove d1 queen, player in the lower band number has white

Basically if the rating difference is less than 100 then the players are in the same band, a band difference of 1 equates to a 100 to 199 rating point difference, 2 band = 200 - 299 difference, 3 band = 300 - 399 difference, etc.

In recent years the winner's rating has varied between about 1500 and 2000 so it doesn't seem to favour any particular level although from experience I would say with large handicaps there is a definite skill for each player in adjusting how they play in terms of risk-taking.


Chess problem by A. G. Kopnin - Russian notation explanation needed [Title "Alexey Grigorievich Kopnin - mate in two - 1948"]
[FEN "nR1rB3/2PPPN2/bbk1N3/1p2p3/1p2P1nq/1K1Pp3/7B/8 w - - 0 1"]

(source)
In this problem, it’s white to move and mate in two. What is the solution?
In the link (source) there is also a solution but it is in Russian notation and I do not understand it. (Maybe I would not understand it even if it was in English notation) I need to see the exact moves explicitly.
Here is the Russian solution:
1.d4! (угроза 2.d5#)
1…ed 2.Kfd8#
1…K:c7 2.Ked8#
1…C:d4 2.cdK#
1…Kf6 2.edK#
1…Л:b8 2.d8K#
(1…Л:e8 2.deФ/C#)

What move is the "1…ed" for example? There are just two columns "ed" but what is the row number and what piece should be moved and where?

What move is the "1…ed" for example?

"ed" indicates that an e pawn takes a d pawn.

Maybe I would not understand it even if it was in English notation

It is actually in algebraic notation. If you follow the link you will find that it even tells you what the Russian abbreviations are for the pieces!
From there it is easy to work out that this is what it means:
[Title "Alexey Grigorievich Kopnin - mate in two - 1948"]
[FEN "nR1rB3/2PPPN2/bbk1N3/1p2p3/1p2P1nq/1K1Pp3/7B/8 w - - 0 1"]

1. d4 {threat d5#} exd4 (1...Nxc7 2. Nexd8#) (1...Bxd4 2. cxd8=N#) (1...Nf6 2. exd8=N#) (1...Rxb8 2. d8=N#) (1...Rxe8 2. dxe8=B#) 2. Nfxd8#

Note that "mate in 2" means that white mates in 2 moves exactly against any defence. Hence listing all the possible black replies to the first move.


Checkmate with king, knight and bishop Today I was playing on a game on chess.com. In that game I lost by time.

[Event "azarigoli vs. vitthal20043"]
[Site "Chess.com"]
[Date "2020-06-11"]
[White "azarigoli"]
[Black "vitthal20043"]
[Result "1-0"]
[WhiteElo "1193"]
[BlackElo "1212"]
[TimeControl "blitz"]
[Termination "azarigoli won on time"]
[FEN ""]
1. c4 b6 2. Nc3 Bb7 3. Nb5 g6 4. d3 Bg7 5. Rb1 a6 6. Na3 d6 7. e4 e6 8. Nh3 Ne7 9. f3 Nd7 10. Bg5 h6 11. Bf4 g5 12. Be3 a5 13. g4 Nc5 14. d4 Nd7 15. Bg2 Ng6 16. d5 e5 17. Nb5 Nc5 18. Bxc5 bxc5 19. a4 c6 20. dxc6 Bxc6 21. Nxd6+ Ke7 22. Nf5+ Kf8 23. Nd6 Bxa4 24. b3 Bc6 25. Rb2 Ra7 26. Rd2 Rd7 27. O-O Ke7 28. Nf5+ Kf8 29. Rxd7 Qxd7 30. Qa1 Qc7 31. Rd1 Ne7 32. Nxe7 Kxe7 33. Bf1 f6 34. Nf2 h5 35. Nd3 Qb6 36. gxh5 Rxh5 37. Bg2 Rh8 38. h3 Rd8 39. Bf1 Rf8 40. Kg2 Ke6 41. Kg3 f5 42. Bg2 fxe4 43. fxe4 Rg8 44. Rf1 Bh8 45. Rf5 Bf6 46. Nxe5 Qxb3+ 47. Bf3 Bxe4 48. Rxf6+ Kxf6 49. Ng4+ Ke7 50. Qf6+ Kd7 51. Qf7+ Kc6 52. Qe6+ Kc7 53. Qxe4 Rf8 54. Qe7+ Kb6 55. Qxf8 a4 56. Qf6+ Ka5 57. Qxg5 a3 58. Qxc5+ Ka4 59. Qc6+ Kb4 60. Ne5 a2 61. Qb6+ Ka3 62. Qa5+ Kb2 63. Qd2+ Ka3 64. Qxa2+ Qxa2 65. c5 Qg8+ 66. Ng4 Qb8+ 67. Kf2 Qb2+ 68. Be2 Qd4+ 69. Ne3 Qxc5 70. Ke1 Qc1+ 71. Kf2 Qh1 72. Bg4 Qh2+ 73. Ng2 Qd6 74. Ne3 1-0

If I captured their pawn with my queen, would it be a draw, or would they have a win? As I would run out of time, that is for sure.

Checkmate is possible with a king, bishop and knight against a bare king, and therefore it would have been a win for white if you timed out before the 50 or 75 move rules came into play. So for instance if the game had gone 72 ... Qxh3 73 Bxg3 and then you timed out within the next 50 moves it would be a win for white.


What is it about Soviet born players that makes them winners in the brutal 128-player knockout format of the World Cup? Teimour Radjabov has just won the World Cup.

The first two FIDE World Cups, in 2000 and 2002 had 4 groups of 6 players with the 2 group winners going into an 8-player knockout. They were both won by Anand and were stand-alone tournaments.

In 2005 the tournament morphed into its current form, a 128 player knockout with a place in the Candidates as the prize (apart from large bundles of cash) played every 2 years.

Knockout is a brutal format which favours the toughest players over the very best. Even though the Soviet Union ceased to exist in 1991 every single winner of the current format World Cup was born in the former USSR. Here is the list:

2005 - Levon Aronian (born 1982 in Yerevan, USSR)
2007 - Gata Kamsky (born 1974 in Novokuznetsk, USSR)
2009 - Boris Gelfand (born 1968 in Minsk, USSR)
2011 - Peter Svidler (born 1976 in Leningrad, USSR)
2013 - Vladimir Kramnik (born 1975 in Tuapse, USSR)
2015 - Sergey Karjakin (born in 1990 in Simferopol, USSR)
2017 - Levon Aronian (born 1982 in Yerevan, USSR)
2019 - Teimour Radjabov (born 1987 in Baku, USSR)

The very best non-USSR players have entered multiple times and failed. Players like Carlsen, Caruana, Ding, Anand have entered but failed to make it all the way though the tough competition.

What is it about Soviet born players that makes them winners in this format?

Most top participants were ex-USSR. Almost all of the World Cups were held in ex-USSR countries. And the rest is coincedence.

Especially in earlier years, most of the top participants were born in the USSR.

E.g. in 2005, the top-25 by rating of the participants was Ivanchuk, Bacrot, Aronian, Grischuk, Gelfand, Shirov, Akopian, Radjabov, Ponomariov, Tiviakov, Sokolov, Dreev, Kamsky, Bologan, Lautier, Bruzon, Bareev, Mamedyarov, Vallejo Pons, Smirin, Harikrishna, Malakhov, Sakaev, Volokitin, Moiseenko.

Only 6 in 25 (Bacrot, Sokolov, Lautier, Bruzon, Vallejo Pons, Harikrishna) were not born in the USSR. And only 1 in the top-10! And that tournament had Kasparov, Kramnik, Anand, Topalov, Svidler and Morozevich (4 out of 6 USSR) missing because of world championship situations.

In later years the number of non-USSR players grew slowly, but in 2011 the first non-USSR player on the list was #12, Zoltan Almasi.

2015 was the first year with only 4 USSR players in the top-10, but 11 in the top-20 (#11 Karjakin won).

It's only in the last few years that it's a bit against the odds that a USSR player won it.

There are of course top non-USSR players: Carlsen, Anand and Topalov were consistently in the top most of this period. But as the World Cup was mostly a qualification event for the Candidates and they qualified otherwise (or were World Champion), they played in very few World Cups.

Apart from 2013, all World Cups were held in USSR countries

Of which three times in Khanty-Mansiysk, Siberia, sometimes in november/december. I think Russian speakers have a psychological advantage in Siberia, they feel more at home because they can at least understand the people.

Coincedence

Taking the facts above, this is easily within the realm of coincedence. I wouldn't bet on a ex-USSR winner next time purely based on the results so far.


Why does Stockfish lose against this piece sacrifice in the Berlin Defense? In a recent YouTube video, Jonathan Schrantz presents an absurd (?) piece sacrifice in the Berlin Defense, which Stockfish seems to vastly underestimate.
The engine evaluation shows around -4, until around move 20, when it "realizes" it actually is not even better and starts playing very weird moves. JS plays a live game against Stockfish on the strongest setting available on Lichess and manages to win.
I assume JS did heavy preparation with alternative engines, as the moves played are by no means natural. But what is really happening here? Is the piece sacrifice actually stronger than Stockfish initially judges? Or is it a bad position, that nonetheless manages to break Stockfish and makes it misplay? Is it due to the limited strength of the featured Lichess engine? Throughout the game, it seems to think that almost every move is still winning, but it actually does not predict the responses played by JS, which lead to a shift in the evaluation after being played.
Below is the game until White reaches a winning position, here is link to the video.
[FEN ""]

1. e4 e5 2. Nf3 Nc6 3. Bb5 Nf6 4. O-O Nxe4 5. d4 Nd6 6. dxe5 { C67 Ruy Lopez: Open Berlin Defense, l'Hermet Variation } Nxb5 7. Re1 a6 8. c4 Nba7 9. Ng5 Be7 10. Qh5 g6 11. Qh6 Bf8 12. Qh3 Bg7 13. Nc3 h6 14. Qg3 O-O 15. Nd5 Nd4 16. Ne4 d6 17. Bg5 hxg5 18. Nef6+ Bxf6 19. exf6 Re8 20. Qxg5 Be6 21. Nf4 Bf5 22. Re7 Bc2 23. Rae1 Nac6 24. Nd5 Rf8 25. R1e3 Nf5 26. Rh3 Bd1 27. Rh6 Qe8 28. Re3 b6 29. Nf4 Bh5 30. Rxh5 b5 31. g4 Qxe3 32. fxe3 Ne5 33. Rh3 Rfc8 34. gxf5 Nf3+ 35. Rxf3

Is it due to the limited strength of the featured Lichess engine?

Most probably it is the above.
Using the engine at lichess.org/analysis (which is Stockfish 13 NNUE, almost the newest version of Stockfish available), on move 20 its eval was -5.9 for Black and it recommended 20...Rxe1+. The move played, 20...Be6, cost Black a significant amount of its advantage (the eval dropped to -2.8), and 21...Bf5 caused another similar drop. In my analysis run, Stockfish 13 NNUE realized Black had lost its advantage as early as 24...Rf8 (0.00 eval). All the above analysis was at rather low depth of ~25, taking only a few seconds to evaluate for me.
I can't tell if JS used Stockfish 12 with NNUE on. If he didn't, it is over a hundred elo weaker than Stockfish 13 NNUE. I note as well that the analysis engine only ran to depth ~16 at most, which is a very shallow depth in engine chess today (it corresponds to searching only ~8 moves ahead - even human GMs can search further than that in some positions).


How to save black's position in this Game? In this game black made some mistakes which leads to the final position.
While analyzing this game the engine is not willing to capture the bishop.

[Event ""]
[Site ""]
[Date "2014.07.05"]
[Round "-"]
[White "ahesham"]
[Black "myking64"]
[Result ""]
[WhiteElo "1455"]
[BlackElo "1398"]
[Time "23:33:01"]
[TimeControl "900"]
[FEN "r1q2r2/1pp2pk1/p1n1bNp1/2b1P1Pp/4PQ1P/8/PPP1BP2/2KR3R w KQkq - 0 1"]

1.Bxh5 gxh5 2.Nxh5+ Kg6 3.Ng3 Be7 4.h5+ Kg7 5.Nf5+ Bxf5 6.exf5

Without capturing the bishop on the 1st move how can I proceed as black ?
What are possible plans for black after the 6th move to get an advantage?

What could be possible plans for black after 6th move to get
  advantage?

None. 1...gxh5 is a huge mistake, after which Black is definitely losing.

   [Date "2014.07.05"]
   [White "ahesham"]
   [Black "myking64"]
   [WhiteElo "1455"]
   [BlackElo "1398"]
   [FEN "r1q2r2/1pp2pk1/p1n1bNp1/2b1P1Pp/4PQ1P/8/PPP1BP2/2KR3R w - - 0 1"]

   1. Bxh5 gxh5 2. Nxh5+ Kg6 3. Ng3 Be7 4. h5+ Kg7 5. Nf5+ Bxf5 6. exf5 Rd8 (6...
   Rg8 7. f6+ Kh8 8. fxe7 Qe6 9. g6 Rg7 10. Qf6 Qxe7 11. h6 Qxf6 12. hxg7+ Kxg7
   13. exf6+ Kxg6 14. Rh3) 7. f6+ Kg8 8. g6 Qe6 9. Qh6 Bxf6 10. exf6 Qxf6 11.
   Rxd8+ Rxd8 12. Rg1 Nd4 13. Qh7+ Kf8 14. g7+ Ke7 15. Qe4+ Ne6 16. Qb4+ Kd7 17.
   g8=Q Rxg8 18. Rxg8 Qxf2 19. Qd2+ Qxd2+ 20. Kxd2

  Without capturing bishop at 1st move how can i proceed as black ?

1...Bd4 is an excellent move, immediately threatening the pawn on e5. The positions that arise after 1...Bd4 are extremely complex. I have attempted to analyze a few with the help of the Houdini 1.5 and Stockfish 4.2 engines. Black is able to hold the position after 1...Bd4 and make a draw.

 [Date "2014.07.05"]
 [White "ahesham"]
 [Black "myking64"]
 [WhiteElo "1455"]
 [BlackElo "1398"]
 [FEN "r1q2r2/1pp2pk1/p1n1bNp1/2b1P1Pp/4PQ1P/8/PPP1BP2/2KR3R w - - 0 1"]

 1. Bxh5 Bd4! 2. Be2 (2. Rxd4 Nxd4 3. Bd1 Rh8 4. c3 Nc6 5. h5 Qd8 6. h6+ Kf8 7.
 Bc2 Qe7 8. h7 Rd8 9. Qh4 Qc5 10. Qh6+ Ke7 11. Qg7 Qxe5 12. Ng8+ (12. Kb1 Rxh7
 13. Qxh7 Qxg5 14. Nd5+ Bxd5 15. exd5 Rxd5) 12... Ke8 13. Nf6+ Ke7 14. Ng8+ Ke8
 15. Nf6+ Ke7) 2... Bxe5 3. Qe3 Qb8!! 4. f4 Qa7 5. Qg3 Bd4 6. Kb1 Qb6 7. c3 Bf2 8.
 Qg2 Rfd8 9. h5 Qe3 10. Bf3 Ne7 11. hxg6 Nxg6 12. Rh7+ Kf8 13. f5 Rxd1+ 14. Bxd1
 Bc4 15. Qh1 Rd8 16. fxg6 Bg1 17. g7+ Ke7 18. g8=N+ Kd6 19. b4 Bd3+ 20. Bc2
 Bxc2+ 21. Kxc2 Qe2+ 22. Kb3 Qd1+ 23. Kb2 Qd2+ 24. Kb1 Qd1+ 25. Kb2 Qd2+