Why is the Budapest Defense considered not fully sound or even dubious? What theoretical difficulties arise for Black? [fen ""]
1. d4 Nf6 2. c4 e5 3. dxe5 Ng4 4. Bf4 (4. Nf3 Bc5 5. e3) (4. e4 Nxe5 5. f4) (4. e3 Nxe5 5. Nh3)

White can choose from multiple setups, most common are 4. Bf4, 4. Nf3, 4. e4 or even 4. e3 with the deep idea of Nh3-f4-d5. Database results favor White heavily. Then again, legends with the caliber of Gelfand or Kramnik go down against it.
From what I gathered, people claim that Black has long-term strategical deficiencies, in many variations White can obtain the bishop pair and the positions are just "good for White". But what exactly are the problems Black faces when playing the Budapest?

EDIT: I have found an interesting line in the Adler-Maroczy Variation (4. Nf3), where I think Black does not have enough compensation. Surprisingly, it is not analysed in any Budapest book I own and played extremely rarely, even though this is the move White wants to play according to most analysis (why is it not checked then???) and it is almost entirely forced.
[fen ""]
1. d4 Nf6 2. c4 e5 3. dxe5 Ng4 4. Nf3 Bc5 5. e3 Nc6 6. Nc3 O-O (6...Ngxe5? 7. Nxe5 Nxe5 8. f4! Ng6 9. Bd3 {is regarded as very good for White and is warned against in almost all Budapest analysis}) 7. Bd3! (7. Be2 Ngxe5 {is normal and Black is fine}) Ngxe5 (7...Re8 8. Qc2 {Black has to somehow block the attack on h7, either by ...g6 or ...h6, both disabling the vital Black plan of Re8-e6-h6 with a kingside attack. White has ideas of returning the pawn on his terms with e6} (8. Bc2 {White achieves a good placement for his bishop without problems})) 8. Bxh7 Kxh7 9. Nxe5 Nxe5 10. Qh5+ Kg8 11. Qxe5 b6 {Black is a pawn down, in return has the bishop pair, but will probably have to forfeit it soon, as ...Bb7 will be blocked by Nd5. White can castle both sides after Bd2}

It's definiely not a "bad" option for Black. It can be played at high levels and still get decent results. However, it's not considered a "great" line for many reasons:

As you said, White has multiple set-ups to choose from most of them leaving them with a slight advantage.
The "surprise factor" that may give Black with an edge against an unprepared opponent doesn't exist (at least not so early in the opening) at the highest levels.
White only enters the Budapest if he wants. If he's worried that his opponent may go for it, he can just play 2.Nf3, most likely transposing later on to his favourite opening.

Database statistics should always be taken with a grain of salt, since there could be multiple factors biasing it (a particular player that uses it very often, or an opening being "the favourite" of weak players, or maybe an opening that is used as a surprise weapon against strong opposition). However I think the factors above prevent the Budapest from being a practical choice to build your repertoire around (specially reason #3: you'll still need something against 2.Nf3, say the King's Indian. You'll be able to use that against 2.c4 too, so you may just as well forget about the Budapest and focus on the King's Indian)


What is a good, aggressive response against the Sicilian Defense? I would like to learn a good response against the Sicilian defense (in your opinion), for both blitz and slower games.

I am looking for a more aggressive response, since it fits best my style. Currently I am trying to learn the Grand Prix attack. I have had good wins with this system but also crushing defeats, and I am wondering if it is the best system to use. I am rated around 1500.

The Open Sicilian (2.Nf3 and 3.d4) is the most aggressive way to attack the Sicilian, as white immediately opens up the position for all his pieces and gets a nice knight on d4. Black has trumps, but first he lags in development and his advantages typically only start counting if he survives white's attack. It is also the best reply, or at least it has consistently been the most popular reply to the Sicilian on higher levels since forever.

So I think that it's really the only correct answer to your question, which asks for the most aggressive and best response to the Sicilian.

That said, it is not the easiest. Black has like ten different ways to react to the Open Sicilian, and although white gets great chances of an attack in almost all of them, they are all different and often black knows them better than white. Spending loads of time learning everything is probably not the most efficient way to improve your chess right now. That is a general thing with chess, and life -- ambitious, good and easy, choose two.

You say "I have had good wins with this system but also crushing defeats". That is good, that is exactly what you expect from aggressive openings, it seems to me.

You also say "I am looking for a more aggressive response, since it fits best my style." That is less good. At top level, having a style at all is a sign of weakness, as it means you are biased. But you're 1500, you don't have a style. You simply have some parts of the game that you are bad at and some parts that you are less bad at. You should be busy identifying things you're bad at and working on them, not worrying about your style.

And, last, losing some games is the worst reason to switch openings! You'll just lose some more games in the next variation you chose, switch again... The Grand Prix is a decent variation, it didn't cause your losses. You made mistakes later on. Find out where, and do better next time.

Understand what happened more generally -- what plan did you choose, how did you expect it to work, why didn't it, is that a problem in general or is it just because of the moves he happened to play this time, in what kind of situations would it work? What other plans are there? Find example games. Regularly switch variations inside the Grand Prix attack, that way you'll see more typical positions and if your opponent does something unexpected, you'll have broader experience to draw from.

Become an expert in your Grand Prix.


Explaining middle game computer analysis I was looking at the computer analysis for a game I played and I need some help to understand a line found by the computer.

After a balanced game (started with a Torre Attack) we arrived at the following position:

You see at the bottom the line suggested by the computer instead of my 23..h6 (that didn't lead anywhere in the end).

This interesting line starts with 23..f3 24. Nxf3. I understand why eventually we arrive at the position below with 27..Be6. But the computer suggests 28.a4 instead of moving the rook. Can you please explain the engine analysis here?

Why doesn't White, for example, exchange their rook with Black’s rook and then play 29. Qe2?

In the first position, f3 is good because it will open the white K after Nxf3 Bg4 then Bxf3 or maybe Rf3 in some cases as the light squares will be very weak (the analysis gave up the Nf3 with Ne5 immediately since the position was so bad that giving up a piece was "best"...if that is best, then it is dead lost). What is left is a HUGE Nc5 compared to a pathetic Bc2.

In the second diagram, you still have that Nc5 vs. the Bc2, but white is already down a piece. That is just lost, and a matter of time.


Why is b3 a blunder? [FEN "r2q2nr/p3kppp/3bp3/2p2b2/Bn1P4/1P2PN2/4NPPP/R1BQ1RK1 b - - 0 13"]

I dont see whats wrong in b3 I am making some space to bring black bishop into game attacking nb4

I wouldn't call it a blunder, as White still has a large advantage after 1.b3. But more efficient is 1.dxc5 Bxc5 2.Bd2. Here White's attacking the knight, but has only spent one tempo developing his bishop. Your idea with 1.b3, 2.Ba3 would take two tempi.

In this kind of position where the opponent's king is vulnerable, each tempo matters more. You want to take advantage of things before the king gets to safety.


ELO change of engine from pure material to very good evaluation I am currently rewriting a chess engine with a friend. We decided to first work on the search and only later if the search works really well, we will do some very good evaluation.

The engine itself evaluates the board with pure material evaluation + piece square tables.
We hit around 6Mnps and it competes with 2000 CCRL engines right now.

I was wondering how much ELO-Gain could we expect if we replace the evaluation at some point with another evaluation.
Or more like: How much ELO can an evaluation function give?

I mean obviously, if you would replace the evaluation of stockfish with nothing but 0, it would do random moves and lose over 3000 ELO points but I am talking about the ELO difference between a very basic evaluation function and an insanely good evaluation function which takes mobility, king safety, pawn structure, game phase, etc. into account.

Greetings,
Finn

The currently best eval function is a leela net. At a single node, some leela nets are in the 2500 elo range. The drawback of course is that they are about 1000x slower than a SF eval (assuming a somewhat modern gpu, cpu). SF eval is obviously way weaker than this, but it wouldn't surprise me if is 500 elo stronger than a simple eval function.


How should I make a 6 year old think more? I have been teaching my 6 year old daughter chess for past 2 years. She plays reasonably well. She often defeats level 25 in Chess Lv 100 app and sometimes Level 6 in Chess.com app. So I am guessing her ELO rating might be around 1200.
I am trying to encourage her to think a little more and be more patient before making an instinctive move. I must have told her a 100 times and shown her effects of not thinking when we analyse the game after she is done. But she continues the same way and does too many errors which she can easily avoid if only she had thought for 5 seconds more. What else can I do to make her understand this?
UPDATE
I have got a lot of answers and useful pointers. Here is a quick summary of suggestions and some of my thoughts.
General

I think some people thought that I train my daughter without her will. May be because of the way I framed the question, English is not my first language. Anyways that is not the case. Whatever is to be done is to be done while understanding a 6 year old's psychology and while ensuring that she continues loving the sport

Every 6 year old (or for that matter a 60 year old) is not the same. So there is no perfect solution that a 6 year old will surely do x or will surely not do y. Even blanket solutions for an average 6 year old kid wouldn't work if it is already established that you are not dealing with an average 6 year old. We have to research/identify/adjust solutions which suit us best.

Solutions like "just keep letting her make mistakes and she will one day understand" have one risk of bad habits getting formed which are extremely difficult to do away. I have seen it happening with kids in other sports. However it also works out fine in many instances.

I think "having fun playing" is not the only motivation. Sure it is the most important one but not the only one. Also various motivations feed into one another. For example, if a kid wins a trophy, he/she will have more fun playing and training which leads to a virtuous cycle. So in the end, it all boils down to striking a right balance between training and having fun. For a 6 year old, probably 90-95% has to be fun.

Best solution is probably to nudge a kid in the right direction but in such a way that kid doesn't feel nudged. It is obviously easier said than done. It has to done in a very subtle and patient way. In my opinion, it is not enough for the kid to enjoy the process. Coach/Teacher/Parent has to enjoy it too.

Biggest takeaways for me are

I shouldn't just be asking her to think more. I have to break down "thinking" more. Feed her questions which I would ask myself before playing a move

I now give more time to analysis of the game after her game with bot is over. We also use a manual chessboard to show where game could have gone if she or the bot had played other move. That engages her better.

Trying to understand her point of view better. Sometimes a moves looks very wrong prima-facie. But I am glad to find that there is a rationale behind it. Sure, it is half-baked and not thoroughly thought out. But that will get fixed if we keep at it.

We play together with higher bot levels. That is fun for me as well as her and is a good way to feed her questions.

Have more variety in play. open ended puzzles, close ended puzzles, blitz, regular, analysis, digital, manual, lower level bot, higher level bot, another human.

Videos if available in your language and Chess Clubs which can provide a good sparring partner should help a lot.

What else can I do to make her understand this

Wait a few years. A 6 year-old's mental capacity is very limited. The good news is that at that age and for several years to come her mental capability is increasing rapidly.

Trying to teach a 6 year old the same way you teach a 12 year old is stupid whether it is maths you are teaching or chess. At 6 the emphasis should be on enjoyment if you still want her to be playing chess at 12.


Efficient ways to go from pseduo legal to fully legal move generation so I've written an entire pseudo legal move generator as well as a simple gui to interface with. I also have my AI only play the best move available without going into a minimax tree. Before I begin any further AI coding I need to factor in putting a king into check and how it changes the list of legal moves. My question is how should i go about this. Given a board state and a list of pseudo legal moves, am I forced to then generate all responses by my opponent to ensure none of these moves will checkmate me? If I go from generating legal moves for 10 of my pieces would I then have to generate all responses to make sure none of those moves result in a checkmate? How also would I go about taking this response-parse requirement for a minimax algorithm? Would I store multiple boards in memory one for each node that I've traversed? Let me know what kind of design principles you think I should look out for.

This is my understanding:

You have a pseudo-legal move generator
Now, you want to get rid of the illegal moves

How serious do you want your engine be? You can always write a function that takes a position and checks your king. Everytime when you wants to check a pseudo-legal move, you call the function. It will definitely work, and it's simple but it's slow.

Let's study at what a modern engine does. The source code for Stockfish is: https://github.com/official-stockfish/Stockfish/blob/master/src/position.cpp

/// Position::legal() tests whether a pseudo-legal move is legal

bool Position::legal(Move m) const {

Check en passant:

// En passant captures are a tricky special case. Because they are rather
// uncommon, we do it simply by testing whether the king is attacked after
// the move is made.

Do you want move your king?

// If the moving piece is a king, check whether the destination
// square is attacked by the opponent. Castling moves are checked
// for legality during move generation.

You can make the move if it's not pinned. Or it's pinned, but it still protects the king.

// A non-king move is legal if and only if it is not pinned or it
// is moving along the ray towards or away from the king.


Free online analysis engine? Is there an online analysis engine that allows you to enter a PGN and get a game analysis, showing where suboptimal moves were made?

I know there are programs for download/purchase that do this, but I specifically want an online one. The ones I've found (e.g.) can analyze positions, but not entire games.

lichess.org has played game analysis and allows you to edit a board before AI game.

Its analysis shows wrong and right moves and percentage statistics of mistakes for both sides.


What are the quckest helpmates delivered by the rook, knight, bishop, and pawn? What are the quickest helpmates, which is where both sides help administer checkmate to one side,  delivered by the rook, knight, bishop, and pawn? The said piece has to deliver the checkmate on the final move.

Here's what I came up with.

Bishop took me 3 moves:

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
1.e4 f5 2.Be2 g5 3.Bh5#  *

Knight took me 3 moves as Black:

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
1.e4 Nc6 2.Ne2 Nd4 3.g3 Nf3#  *

Pawn took me 5 moves:

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
1.e4 Na6 2.Bc4 Nb4 3.e5 Na6 4.e6 Nc5 5.exf7#  *

Rook initially took me 6 moves, with 1.h4 f5 2.Rh3 f4 3.d4 f3 4.Rxf3 g6 5.Bh6 Nc6 6.Rxf8#. But I found a quicker way to checkmate with a rook - promote to one! This results in a checkmate in 5:

[FEN "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"]
1. g4 Nh6 2. g5 g6 3. gxh6 Bg7 4. hxg7 Na6 5. gxh8=R#


King taking pieces when check Why can the white king not take the queen here?

Because that would move the king into check - the queen is defended by the bishop on c5.

More generally there is no problem with a king taking a piece that is checking it, provided the capture does not move the king into check or break any of the other laws of chess.


Would a professional level player put their queen in danger of capture from the opposing queen with protection? Every now and then I will move my queen into a position that puts it in position to be captured by the opposing queen. Sometimes my opponents takes it and I capture their queen immediately. Also, sometimes they don't take it and neither of use loses a queen.

Is it ever smart, except for obvious occasions, to lose your queen just to take the opposing sides queen?

You're referring to a queen trade, and yes, there're plenty of situations in which you want to trade queens. In general, trading queens simplifies the position, which is good if:

You're up material. The fewer pieces there are on the board, the harder it is for the opponent to cook up counterplay.
You're on the defensive. The fewer pieces there are on the board, the harder it is to launch a successful attack on the enemy king.
You have some kind of advantage that makes you win the endgame, e.g. fewer pawn islands (this is a technical chess concept that measures on how many separated pawns you have), an outside passed pawn, and so on.
Various other reasons (there are a ton of them).

Here's an example from the recent game Topalov-Maxime Vachier Lagrave.

1kr5/1r3p2/2np3p/p5p1/2P3P1/PPNq4/K1R3QP/7B w - - 0 39

Black has just played Qe3-d3, and it's White's turn. It should be clear that Black's queen is much stronger than White's right now: it's much more aggressively positioned and it's generating a lot of threats. So Topalov played 39. Qd2, offering the trade. MVL promptly played 39...Qxd2, because if he didn't, White would play Qxd6+, eating a pawn for free.

This kind of exchange happens all the time at top level.


How to improve king safety I really wish to improve my chess skills a bit, albeit I am pretty sure that I do not want to become a grandmaster.

One of my problem is my king's safety. Chess is very different from some other board games. E.g. in checkers you must either kill or immobilize every single opponent's pieces in order to win; however, the rule of mandatory capture repulses me quite a lot from playing draughts. Chess is much nicer, it's more elegant and has much more possibilities. But having your queen, rooks, bishops, knights and pawns in good squares, a good attacking position and knowing strategy and tactics, openings and endgames etc. is nothing if you are so, so bad at providing safety for your king.

In fact, I would say I'm quite good in endgames where pieces are so few. If I have a pawn or a piece advantage and manage to get to the endgame, then I can make my way to a win. But my opponent rarely allows me to play so many moves. The game ends in the opening or middlegame. That is, I'd like to say I've studied fool's mate, scholar's mate and so on. I know how to avoid them. Most often, the opponent checkmates me in the middlegame.

I've seen a couple of great chess games on youtube. For example, 1851 "immortal game" (Anderssen–Kieseritzky) impressed me so much. And of course, using my chessboard I studied (played back) quite a bunch of other famous games played by very good chess players. Many of them seem to have the same theme: the stronger player constantly gives checks and thus blocks a good majority of squares around the opponent's king. Then, he/she delivers checkmate, using a great advantage from those blocked squares.

I am not sure if I should keep my own king open or closed. An open (bare) king seems to be a bad thing since it is very easily separated from my pieces and then driven to the edge of the board. But isn't a king surrounded by friendly pieces from different sides even worse? They are used as an advantage by the opponent. Moreover, I am often checkmated with a knight, so it can be a smothered checkmate.

Unfortunately, my search for "king safety" on this site did not provide too much useful information.

The question is if they are any videos or maybe sites or written material which would help me to improve my king's safety? Apart from very obvious advice, e.g. an early castling. Believe me, I know my castling well.

When playing chess, I still try to concentrate on capturing enemy pieces and thus to make my way to the endgame. I know it can be criticized but it's my style.

It's a very general question, no concrete examples (where you struggle to defend) are provided in your post, and as such one cannot really answer meaningfully. However, here are some rough hints that might help you:

Pawn structure is a key factor in king safety. Any pawn move commitments on the side you've castled should be taken into account with extreme care, else you're irreversibly creating hooks for your opponents attacks or simply holes for the opponent's pieces to land on. E.g., when you castle short and play h3, when your opponent hasn't castled short, there's a very concrete attack threat on your king: black pushes the g and h pawns and opens a file towards your king, as g4 will challenge h3, and often however you react to it, a file will eventually open. Instead if all the pawns are on the starting squares, it's very hard for your opponent to find a breakthrough (for more on this see the discussions here and in particular the showcased Kasparov game).

For a good example, see the game of Aronian vs Kramnik from 2018 candidates: notice how Kramnik exploited the h3 hook to create a devastasting attack on white's king.

Similarly argued, if you finachetto your bishop on a castled side (e.g. g3-Bg2), and lose/trade that bishop, all the weakened squares  turn into holes (entry points) for your opponent's pieces towards your king.

Defending pieces: Another aspect to king safety is presence of defending pieces, e.g. if you castle short and all your minor pieces are on the queenside, your king's left naked and can be easily prone to various sacrificial attacks which you won't be in time to defend.

Here are some diagrams showing some typical examples:

Left:h3, a hook for your opponent's attack.
Mid: Weakened Fianchetto structure.
right: knights are great defenders.

Neutralize opponent's key attacking pieces: Given your established structure on the side you've castled, or simply where your king stands, ask yourself which of your opponent's pieces can best exploit these weaknesses against your king and try to force a trade of those pieces. And vice versa, try to preserve your good defenders by disallowing your opponent from easily forcing an exchange.

Play for initiative: Try to create threats and attacks to divert some of your opponent's play and pieces away from your king. If you pose no challenge to your opponent, they will simply mount everything they have onto your king. To play the defense side is always harder, as you have to consider all the tactical options for your opponent in order to defend against them, whereas for them, if a tactic works or not is not a major risk (unless they've sacrificed heavily of course) as either way it doesn't concern their king.

Anyhow, the list goes on and this is by no means exhaustive, but it hopefully gives you additional hints for how to think about your king's safety.


What is the right defensive set-up for the King-Bishop_Rook trio in the diagrammed position? It's Black's move in the diagram.

In a recent correspondence game I managed to win an exchange at a cost of weakening my kingside a little bit. In the diagrammed position the g-pawn is missing and the White queen is lurking around. You also see the dark-squared bishop as a potentially aggressive resource for white. Seeing all of this coming my question was:

1. What are the right squares for the king?

2. Should I push my h-pawn to h6? (I will probably have to play e6 to protect f5, so, Bg5-f6 is a threat.

3. Do I put my rook on g-file? In the actual game I did, but that ended up smothering my king in the corner and for a long time to come gave tactical traps to my opponent.

Is there a general guide for how to defend such weakened structures? Like how to cover up for a missing h-pawn, or g-pawn, or f-pawn?

Thanks for your time.

[fen "5rk1/2q1ppbp/p1p5/2N1Pp2/8/2PP2Q1/P1P3PP/1rB2RK1 b - - 0 1"]

1...Qxe5 2. Qxe5 Bxe5 3. Nd7 Bxc3 4. Nxf8 Bd4+ 5. Kh1 Be3

FYI: I can't take on e5 due to the exchange followed by knight fork :(

You forgot to say who has the move in the given position. This is always important.

For example, here if White has the move, he can attack with 1.Bh6, and he will be up a piece.

So we can assume that Black has the move.

In that case he had better play 1...Kh8 to avoid White's attack with 2.Bh6. This move also frees Black's bishop, so White should probably defend the pawn with 2.d4 and Black will probably need to play 2...Rg8. This already answers a couple of your questions (the king needs to go to h8, and the rook will go to g8).

But I leave the other points to better players...


What is the longest checkmate problem a human has composed? Well, I looked at some long checkmates, and I wonder, what is the longest checkmate a human has composed?

The longest known checkmate problem composed by a human is dependent on a few criteria that are generally used by chess composers. Namely, it is a question of whether or not you want the problem to have a unique solution, meaning that there is only one possible solution with Black defending optimally, and if you want the position to be legal or not, meaning that it is reachable from the starting position. Another consideration is whether or not promoted pieces are allowed, as most composers try to not use them. Finally, it is also debatable whether or not an illegal position must have only pieces from the chess box, with pawns being converted as needed.
Here is a selection of a few problems that fall along these lines.
This is the longest legal problem with a unique solution and no promoted pieces.
[Title "Walther Jørgensen, Thema Danicum 1982, Mate In 226"]
[fen "1N2Q3/p6n/p5n1/p1p2rpb/p4k1r/K1P4p/2PP4/6B1 w - - 0 1"]

1. Bh2+! Kf3 2. Qe3+ Kg2 3. Qg1+ Kf3 4. Qf1+ Kg4 5. Qe2+ Rf3 6. Qe6+ Rf5 7. Nd7 Kf3 8. Qe3+ Kg2 9. Qg1+ Kf3 10. Qf1+ Kg4 11. Qe2+ Rf3 12. Qe6+ Rf5 13. Kb2! Kf3 14. Qe3+ Kg2 15. Qg1+ Kf3 16. Qf1+ Kg4 17. Qe2+ Rf3 18. Qe6+ Rf5 19. Kc1! Kf3 20. Qe3+ Kg2 21. Qg1+ Kf3 22. Qf1+ Kg4 23. Qe2+ Rf3 24. Qe6+ Rf5 25. Kd1! a3! 26. Kc1 Kf3 27. Qe3+ Kg2 28. Qg1+ Kf3 29. Qf1+ Kg4 30. Qe2+ Rf3 31. Qe6+ Rf5 32. Kb1 Kf3 33. Qe3+ Kg2 34. Qg1+ Kf3 35. Qf1+ Kg4 36. Qe2+ Rf3 37. Qe6+ Rf5 38. Ka2 Kf3 39. Qe3+ Kg2 40. Qg1+ Kf3 41. Qf1+ Kg4 42. Qe2+ Rf3 43. Qe6+ Rf5 44. Kxa3 Kf3 45. Qe3+ Kg2 46. Qg1+ Kf3 47. Qf1+ Kg4 48. Qe2+ Rf3 49. Qe6+ Rf5 50. Kb2 Kf3 51. Qe3+ Kg2 52. Qg1+ Kf3 53. Qf1+ Kg4 54. Qe2+ Rf3 55. Qe6+ Rf5 56. Kc1 Kf3 57. Qe3+ Kg2 58. Qg1+ Kf3 59. Qf1+ Kg4 60. Qe2+ Rf3 61. Qe6+ Rf5 62. Kd1 a4! 63. Kc1 Kf3 64. Qe3+ Kg2 65. Qg1+ Kf3 66. Qf1+ Kg4 67. Qe2+ Rf3 68. Qe6+ Rf5 69. Kd1 a5! 70. Kc1 Kf3 71. Qe3+ Kg2 72. Qg1+ Kf3 73. Qf1+ Kg4 74. Qe2+ Rf3 75. Qe6+ Rf5 76. Kd1 a6! 77. Kc1 Kf3 78. Qe3+ Kg2 79. Qg1+ Kf3 80. Qf1+ Kg4 81. Qe2+ Rf3 82. Qe6+ Rf5 83. Kd1 a3 84. Kc1 Kf3 85. Qe3+ Kg2 86. Qg1+ Kf3 87. Qf1+ Kg4 88. Qe2+ Rf3 89. Qe6+ Rf5 90. Kb1 Kf3 91. Qe3+ Kg2 92. Qg1+ Kf3 93. Qf1+ Kg4 94. Qe2+ Rf3 95. Qe6+ Rf5 96. Ka2 Kf3 97. Qe3+ Kg2 98. Qg1+ Kf3 99. Qf1+ Kg4 100. Qe2+ Rf3 101. Qe6+ Rf5 102. Kxa3 Kf3 103. Qe3+ Kg2 104. Qg1+ Kf3 105. Qf1+ Kg4 106. Qe2+ Rf3 107. Qe6+ Rf5 108. Kb2 Kf3 109. Qe3+ Kg2 110. Qg1+ Kf3 111. Qf1+ Kg4 112. Qe2+ Rf3 113. Qe6+ Rf5 114. Kc1 Kf3 115. Qe3+ Kg2 116. Qg1+ Kf3 117. Qf1+ Kg4 118. Qe2+ Rf3 119. Qe6+ Rf5 120. Kd1 a4! 121. Kc1 Kf3 122. Qe3+ Kg2 123. Qg1+ Kf3 124. Qf1+ Kg4 125. Qe2+ Rf3 126. Qe6+ Rf5 127. Kd1 a5! 128. Kc1 Kf3 129. Qe3+ Kg2 130. Qg1+ Kf3 131. Qf1+ Kg4 132. Qe2+ Rf3 133. Qe6+ Rf5 134. Kd1 a3 135. Kc1 Kf3 136. Qe3+ Kg2 137. Qg1+ Kf3 138. Qf1+ Kg4 139. Qe2+ Rf3 140. Qe6+ Rf5 141. Kb1 Kf3 142. Qe3+ Kg2 143. Qg1+ Kf3 144. Qf1+ Kg4 145. Qe2+ Rf3 146. Qe6+ Rf5 147. Ka2 Kf3 148. Qe3+ Kg2 149. Qg1+ Kf3 150. Qf1+ Kg4 151. Qe2+ Rf3 152. Qe6+ Rf5 153. Kxa3 Kf3 154. Qe3+ Kg2 155. Qg1+ Kf3 156. Qf1+ Kg4 157. Qe2+ Rf3 158. Qe6+ Rf5 159. Kb2 Kf3 160. Qe3+ Kg2 161. Qg1+ Kf3 162. Qf1+ Kg4 163. Qe2+ Rf3 164. Qe6+ Rf5 165. Kc1 Kf3 166. Qe3+ Kg2 167. Qg1+ Kf3 168. Qf1+ Kg4 169. Qe2+ Rf3 170. Qe6+ Rf5 171. Kd1 a4 172. Kc1 Kf3 173. Qe3+ Kg2 174. Qg1+ Kf3 175. Qf1+ Kg4 176. Qe2+ Rf3 177. Qe6+ Rf5 178. Kd1 c4! 179. Kc1 Kf3 180. Qe3+ Kg2 181. Qg1+ Kf3 182. Qf1+ Ke4! 183. Qxc4+ Kf3 184. Qf1+ Kg4 185. Qe2+ Rf3 186. Qe6+ Rf5 187. Kd1 a3 188. Kc1 Kf3 189. Qe3+ Kg2 190. Qg1+ Kf3 191. Qf1+ Kg4 192. Qe2+ Rf3 193. Qe6+ Rf5 194. Kb1 Kf3 195. Qe3+ Kg2 196. Qg1+ Kf3 197. Qf1+ Kg4 198. Qe2+ Rf3 199. Qe6+ Rf5 200. Ka2 Kf3 201. Qe3+ Kg2 202. Qg1+ Kf3 203. Qf1+ Kg4 204. Qe2+ Rf3 205. Qe6+ Rf5 206. Kxa3 Kf3 207. Qe3+ Kg2 208. Qg1+ Kf3 209. Qf1+ Kg4 210. Qe2+ Rf3 211. Qe6+ Rf5 212. Kb2 Kf3 213. Qe3+ Kg2 214. Qg1+ Kf3 215. Qf1+ Kg4 216. Qe2+ Rf3 217. Qe6+ Rf5 218. Kc1 Kf3 219. Qe3+ Kg2 220. Qg1+ Kf3 221. Qf1+ Kg4 222. Qe2+ Rf3 223. Qe6+ Rf5 224. Kd1 Nf8,Nf6 225. Nf6+ Kf3 226. Qe2#

Based off of an earlier mate in 292 with an illegal position, this mate in 257 has as legal position with some minor duals in the solution.
[Title "Ottó Titusz Bláthy, Vielzügige Schachaufg 1889, Mate In 257 Legal Version of the #292"]
[FEN "q5nn/1pk1p3/p3P1p1/P3rpP1/1Kp1pP1p/8/2PQ1PP1/8 w - - 0 1"]

1. Qd7+ Kb8 2. Qd8+ Ka7 3. Qd4+ Rc5 4. Qxc5+ Kb8 5. Qe5+ Kc8 6. Qd5 Kc7 7. Qd7+ Kb8 8. Qd8+ Ka7 9. Qb6+ Kb8 10. c3 Kc8 11. Qc5+ Kb8 12. Qe5+ Kc8 13. Qd5 Kc7 14. Qd7+ Kb8 15. Qd8+ Ka7 16. Qb6+ Kb8 17. Ka3 Kc8 18. Qc5+ Kb8 19. Qe5+ Kc8 20. Qd5 Kc7 21. Qd7+ Kb8 22. Qd8+ Ka7 23. Qb6+ Kb8 24. Kb2 Kc8 25. Qc5+ Kb8 26. Qe5+ Kc8 27. Qd5 Kc7 28. Qd7+ Kb8 29. Qd8+ Ka7 30. Qb6+ Kb8 31. Kc1 Kc8 32. Qc5+ Kb8 33. Qe5+ Kc8 34. Qd5 Kc7 35. Qd7+ Kb8 36. Qd8+ Ka7 37. Qb6+ Kb8 38. Kd1 Kc8 39. Qc5+ Kb8 40. Qe5+ Kc8 41. Qd5 Kc7 42. Qd7+ Kb8 43. Qd8+ Ka7 44. Qb6+ Kb8 45. Ke2 Kc8 46. Qc5+ Kb8 47. Qe5+ Kc8 48. Qd5 Kc7 49. Qd7+ Kb8 50. Qd8+ Ka7 51. Qb6+ Kb8 52. Kf1 Kc8 53. Qc5+ Kb8 54. Qe5+ Kc8 55. Qd5 Kc7 56. Qd7+ Kb8 57. Qd8+ Ka7 58. Qb6+ Kb8 59. Kg1 Kc8 60. Qc5+ Kb8 61. Qe5+ Kc8 62. Qd5 Kc7 63. Qd7+ Kb8 64. Qd8+ Ka7 65. Qb6+ Kb8 66. Kh2 Kc8 67. Qc5+ Kb8 68. Qe5+ Kc8 69. Qd5 Kc7 70. Qd7+ Kb8 71. Qd8+ Ka7 72. Qb6+ Kb8 73. Kh3 Kc8 74. Qc5+ Kb8 75. Qe5+ Kc8 76. Qd5 Kc7 77. Qd7+ Kb8 78. Qd8+ Ka7 79. Qb6+ Kb8 80. Kxh4 Kc8 81. Qc5+ Kb8 82. Qe5+ Kc8 83. Qd5 Kc7 84. Qd7+ Kb8 85. Qd8+ Ka7 86. Qb6+ Kb8 87. Kh3 Kc8 88. Qc5+ Kb8 89. Qe5+ Kc8 90. Qd5 Kc7 91. Qd7+ Kb8 92. Qd8+ Ka7 93. Qb6+ Kb8 94. Kh2 Kc8 95. Qc5+ Kb8 96. Qe5+ Kc8 97. Qd5 Kc7 98. Qd7+ Kb8 99. Qd8+ Ka7 100. Qb6+ Kb8 101. Kg1 Kc8 102. Qc5+ Kb8 103. Qe5+ Kc8 104. Qd5 Kc7 105. Qd7+ Kb8 106. Qd8+ Ka7 107. Qb6+ Kb8 108. Kf1 Kc8 109. Qc5+ Kb8 110. Qe5+ Kc8 111. Qd5 Kc7 112. Qd7+ Kb8 113. Qd8+ Ka7 114. Qb6+ Kb8 115. Ke2 Kc8 116. Qc5+ Kb8 117. Qe5+ Kc8 118. Qd5 Kc7 119. Qd7+ Kb8 120. Qd8+ Ka7 121. Qb6+ Kb8 122. Kd1 Kc8 123. Qc5+ Kb8 124. Qe5+ Kc8 125. Qd5 Kc7 126. Qd7+ Kb8 127. Qd8+ Ka7 128. Qb6+ Kb8 129. Kc1 Kc8 130. Qc5+ Kb8 131. Qe5+ Kc8 132. Qd5 Kc7 133. Qd7+ Kb8 134. Qd8+ Ka7 135. Qb6+ Kb8 136. Kb2 Kc8 137. Qc5+ Kb8 138. Qe5+ Kc8 139. Qd5 Kc7 140. Qd7+ Kb8 141. Qd8+ Ka7 142. Qb6+ Kb8 143. Ka3 Kc8 144. Qc5+ Kb8 145. Qe5+ Kc8 146. Qd5 Kc7 147. Qd7+ Kb8 148. Qd8+ Ka7 149. Qb6+ Kb8 150. Kb4 Kc8 151. Qc5+ Kb8 152. Qe5+ Ka7 153. Qd4+ Kb8 154. Qxh8 Kc7 155. Qe5+ Kc8 156. Qd5 Kb8 157. Qd8+ Ka7 158. Qb6+ Kb8 159. Ka3 Kc8 160. Qc5+ Kb8 161. Qe5+ Kc8 162. Qd5 Kc7 163. Qd7+ Kb8 164. Qd8+ Ka7 165. Qb6+ Kb8 166. Kb2 Kc8 167. Qc5+ Kb8 168. Qe5+ Kc8 169. Qd5 Kc7 170. Qd7+ Kb8 171. Qd8+ Ka7 172. Qb6+ Kb8 173. Kc1 Kc8 174. Qc5+ Kb8 175. Qe5+ Kc8 176. Qd5 Kc7 177. Qd7+ Kb8 178. Qd8+ Ka7 179. Qb6+ Kb8 180. Kd1 Kc8 181. Qc5+ Kb8 182. Qe5+ Kc8 183. Qd5 Kc7 184. Qd7+ Kb8 185. Qd8+ Ka7 186. Qb6+ Kb8 187. Ke2 Kc8 188. Qc5+ Kb8 189. Qe5+ Kc8 190. Qd5 Kc7 191. Qd7+ Kb8 192. Qd8+ Ka7 193. Qb6+ Kb8 194. Kf1 Kc8 195. Qc5+ Kb8 196. Qe5+ Kc8 197. Qd5 Kc7 198. Qd7+ Kb8 199. Qd8+ Ka7 200. Qb6+ Kb8 201. Kg1 Kc8 202. Qc5+ Kb8 203. Qe5+ Kc8 204.Qd5 Kc7 205. Qd7+ Kb8 206. Qd8+ Ka7 207. Qb6+ Kb8 208. Kh2 Kc8 209. Qc5+ Kb8 210. Qe5+ Kc8 211. Qd5 Kc7 212. Qd7+ Kb8 213. Qd8+ Ka7 214. Qb6+ Kb8 215. Kh3 Kc8 216. Qc5+ Kb8 217. Qe5+ Kc8 218. Qd5 Kc7 219. Qd7+ Kb8 220. Qd8+ Ka7 221. Qb6+ Kb8 222. g4 Kc8 223. Qc5+ Kb8 224. Qe5+ Kc8 225. Qd5 Kc7 226. Qd7+ Kb8 227. Qd8+ Ka7 228. Qb6+ Kb8 229. gxf5 gxf5 230. Kh4 Kc8 231. Qc5+ Kb8 232. Qe5+ Kc8 233. Qd5 Kc7 234. Qd7+ Kb8 235. Qd8+ Ka7 236. Qb6+ Kb8 237. Kh5 Kc8 238. Qc5+ Kb8 239. Qe5+ Kc8 240. Qd5 Kc7 241. Qd7+ Kb8 242. Qd8+ Ka7 243. Qb6+ Kb8 244. Kg6 Kc8 245. Qc5+ Kb8 246. Qe5+ Kc8 247. Qd5 Kc7 248. Qd7+ Kb8 249. Qd8+ Ka7 250. Qb6+ Kb8 251. Kf7 Kc8 252. Ke8 Kb8 253. Kd7 e3 254. fxe3 Nf6+ 255. gxf6 exf6  256. e7 Qa7 257. e8=Q#

Here is the longest problem that has a promoted piece and some minor duals in the solution.
[Title "Nenad Petrovic, Zagreb 1969, Mate In 271"]
[FEN "8/Bk3p1p/1P3p2/KP2n2p/1P1p4/1Pp2p2/B1P5/7B w - - 0 1"]

1. Bb1 h4 2. Ka4 Ka8 3. Ka3 Kb7 4. Ka2 Ka8 5. Ka1 Kb7 6. Ba2 Ka8 7. Kb1 Kb7 8. Kc1 Ka8 9. Kd1 Kb710. Ke1 Ka8 11. Bb1 Kb7 12. Kf1 Ka8 13. Kf2 Kb7 14. Ke1 Ka8 15. Kd1 Kb7 16. Kc1 Ka8 17. Ba2 Kb7 18. Kb1 Ka8 19. Ka1 Kb7 20. Bb1 Ka8 21. Ka2 Kb7 22. Ka3 Ka8 23. Ka4 Kb7 24. Ka5 f5 25. Ka4 Ka8 26. Ka3 Kb7 27. Ka2 Ka8 28. Ka1 Kb7 29. Ba2 Ka8 30. Kb1 Kb7 31. Kc1 Ka8 32. Kd1 Kb7 33. Ke1 Ka8 34. Bb1 Kb7 35. Kf1 Ka8 36. Kf2 Kb7 37. Ke1 Ka8 38. Kd1 Kb7 39. Kc1 Ka8 40. Ba2 Kb7 41. Kb1 Ka8 42. Ka1 Kb7 43. Bb1 Ka8 44. Ka2 Kb7 45. Ka3 Ka8 46. Ka4 Kb7 47. Ka5 f4 48. Ka4 Ka8 49. Ka3 Kb7 50. Ka2 Ka8 51. Ka1 Kb7 52. Ba2 Ka8 53. Kb1 Kb7 54. Kc1 Ka8 55. Kd1 Kb7 56. Bb1 Ka8 57. Ke1 Kb7 58. Kf1 Ka8 59. Kf2 Kb7 60. Ke1 Ka8 61. Kd1 Kb7 62. Kc1 Ka8 63. Ba2 Kb7 64. Kb1 Ka8 65. Ka1 Kb7 66. Bb1 Ka8 67. Ka2 Kb7 68. Ka3 Ka8 69. Ka4 Kb7 70. Ka5 f6 71. Ka4 Ka8 72. Ka3 Kb7 73. Ka2 Ka8 74. Ka1 Kb7 75. Ba2 Ka8 76. Kb1 Kb7 77. Kc1 Ka8 78. Kd1 Kb7 79. Ke1 Ka8 80. Bb1 Kb7 81. Kf1 Ka8 82. Kf2 Kb7 83. Ke1 Ka8 84. Kd1 Kb7 85. Kc1 Ka8 86. Ba2 Kb7 87. Kb1 Ka8 88. Ka1 Kb7 89. Bb1 Ka8 90. Ka2 Kb7 91. Ka3 Ka8 92. Ka4 Kb7 93. Ka5 f5 94. Ka4 Ka8 95. Ka3 Kb7 96. Ka2 Ka8 97. Ka1 Kb7 98. Ba2 Ka8 99. Kb1 Kb7 100. Kc1 Ka8 101. Kd1 Kb7 102. Ke1 Ka8 103. Bb1 Kb7 104. Kf1 Ka8 105. Kf2 Kb7 106. Ke1 Ka8 107. Kd1 Kb7 108. Kc1 Ka8 109. Ba2 Kb7 110. Kb1 Ka8 111. Ka1 Kb7 112. Bb1 Ka8 113. Ka2 Kb7 114. Ka3 Ka8 115. Ka4 Kb7. 116. Ka5 h3 117. Ka4 Ka8 118. Ka3 Kb7 119. Ka2 Ka8 120. Ka1 Kb7 121. Ba2 Ka8 122. Kb1 Kb7 123. Kc1 Ka8 124. Kd1 Kb7 125. Ke1 Ka8 126. Bb1 Kb7 127. Kf1 Ka8 128. Kf2 Kb7 129. Ke1 Ka8 130. Kd1 Kb7 131. Kc1 Ka8 132. Ba2 Kb7 133. Kb1 Ka8 134. Ka1 Kb7 135. Bb1 Ka8 136. Ka2 Kb7 137. Ka3 Ka8 138. Ka4 Kb7 139. Ka5 h2 140. Ka4 Ka8 141. Ka3 Kb7 142. Ka2 Ka8 143. Ka1 Kb7 144. Ba2 Ka8 145. Kb1 Kb7 146. Kc1 Ka8 147. Kd1 Kb7 148. Ke1 Ka8 149. Bb1 Kb7 150. Kf1 Ka8 151. Kf2 Kb7 152. Ke1 Ka8 153. Kd1 Kb7 154. Kc1 Ka8 155. Ba2 Kb7 156. Kb1 Ka8 157. Ka1 Kb7 158. Bb1 Ka8 159. Ka2 Kb7 160. Ka3 Ka8 161. Ka4 Kb7 162. Ka5 h6 163. Ka4 Ka8 164. Ka3 Kb7 165. Ka2 Ka8 166. Ka1 Kb7 167. Ba2 Ka8 168. Kb1 Kb7 169. Kc1 Ka8 170. Kd1 Kb7 171. Ke1 Ka8 172. Bb1 Kb7 173. Kf1 Ka8 174. Kf2 Kb7 175. Ke1 Ka8 176. Kd1 Kb7 177. Kc1 Ka8 178. Ba2 Kb7 179. Kb1 Ka8 180. Ka1 Kb7 181. Bb1 Ka8 182. Ka2 Kb7 183. Ka3 Ka8 184. Ka4 Kb7 185. Ka5 h5 186. Ka4 Ka8 187. Ka3 Kb7 188. Ka2 Ka8 189. Ka1 Kb7 190. Ba2 Ka8 191. Kb1 Kb7 192. Kc1 Ka8 193. Kd1 Kb7 194. Ke1 Ka8 195. Bb1 Kb7 196. Kf1 Ka8 197. Kf2 Kb7 198. Ke1 Ka8 199. Kd1 Kb7 200. Kc1 Ka8 201. Ba2 Kb7 202. Kb1 Ka8 203. Ka1 Kb7 204. Bb1 Ka8 205. Ka2 Kb7 206. Ka3 Ka8 207. Ka4 Kb7 208. Ka5 h4 209. Ka4 Ka8 210. Ka3 Kb7 211. Ka2 Ka8 212. Ka1 Kb7 213. Ba2 Ka8 214. Kb1 Kb7 215. Kc1 Ka8 216. Kd1 Kb7 217. Ke1 Ka8 218. Bb1 Kb7 219. Kf1 Ka8 220. Kf2 Kb7 221. Ke1 Ka8 222. Kd1 Kb7 223. Kc1 Ka8 224. Ba2 Kb7 225. Kb1 Ka8 226. Ka1 Kb7 227. Bb1 Ka8 228. Ka2 Kb7 229. Ka3 Ka8 230. Ka4 Kb7 231. Ka5 h3 232. Ka4 Ka8 233. Ka3 Kb7 234. Ka2 Ka8 235. Ka1 Kb7 236. Ba2 Ka8 237. Kb1 Kb7 238. Kc1 Ka8 239. Kd1 Kb7 240. Ke1 Ka8 241. Bb1 Kb7 242. Kf1 Ka8 243. Kf2 Kb7 244. Ke1 Ka8 245. Kd1 Kb7 246. Kc1 Ka8 247. Ba2 Kb7 248. Kb1 Ka8 249. Ka1 Kb7 250. Bb1 Ka8 251. Ka2 Kb7 252. Ka3 Ka8 253. Ka4 Kb7 254. Ka5 Kc8 255. Ka6 Kd8 256. b7 Nd7 257. Bxf3 h1=Q 258. Bxh1 d3 259. cxd3 f3 260. Bxf3 Ke7 261. b8=Q Nxb8+ 262. Bxb8 c2 263. Bxc2 Ke6 264. b6 Kf6 265. b7 Ke6 266. d4 h2 267. Bxh2 f4 268. b8=Q Kf7 269. Bxf4  Kg7 270. Bh5 Kf6 271. Qe5#

In regards to the longest known correct checkmate in an illegal position that uses just pieces from the chess box, as Blathy repurposed the the light squared bishop onto a dark square.
Note-Althogh Blathy is known to have composed to slightly longer dualed, illegal mate in 292 moves, that problem is cooked, meaning it is incorrect and has a shorter solution although I still searching for an exact mention of where in the problem are the moves that Blathy missed in his analysis.
[Title "Otto Blathy, Weihnachtsgrüße 12/1929, Mate In 290"]
[FEN "bBrb1B2/P1n1r2p/1Kp1Pb1p/2pk1P1p/5P2/1P2pP2/1pP1P3/1R4n1 w - - 0 1"]

1. Rd1+ Bd4 2. c4+ Kd6 3. Rxg1 Bc3 4. Rd1+ Bd4 5. Ka5 Bb7 6. Ka4 Ba8 7. Ka3 Bb7 8. Ka2 Ba8 9. Kb1 Bb7 10. Kc2 Ba8 11. Kd3 Bb7 12. Re1 Ba8 13. Rf1 Bb7 14. Rd1 Ba8 15. Kc2 Bb7 16. Kb1 Ba8 17. Ka2 Bb7 18. Ka3 Ba8 19. Ka4 Bb7 20. Ka5 Ba8 21. Kb6 h4 22. Ka5 Bb7 23. Ka4 Ba8 24. Ka3 Bb7 25. Ka2 Ba8 26. Kb1 Bb7 27. Kc2 Ba8 28. Kd3 Bb7 29. Rf1 Ba8 30. Re1 Bb7 31. Rd1 Ba8 32. Kc2 Bb7 33. Kb1 Ba8 34. Ka2 Bb7 35. Ka3 Ba8 36. Ka4 Bb7 37. Ka5 Ba8 38. Kb6 h3 39. Ka5 Bb7 40. Ka4 Ba8 41. Ka3 Bb7 42. Ka2 Ba8 43. Kb1 Bb7 44. Kc2 Ba8 45. Kd3 Bb7 46. Rf1 Ba8 47. Re1 Bb7 48. Rd1 Ba8 49. Kc2 Bb7 50. Kb1 Ba8 51. Ka2 Bb7 52. Ka3 Ba8 53. Ka4 Bb7 54. Ka5 Ba8 55. Kb6 h2 56. Ka5 Bb7 57. Ka4 Ba8 58. Ka3 Bb7 59. Ka2 Ba8 60. Kb1 Bb7 61. Kc2 Ba8 62. Kd3 Bb7 63. Rf1 Ba8 64. Re1 Bb7 65. Rd1 Ba8 66. Kc2 Bb7 67. Kb1 Ba8 68. Ka2 Bb7 69. Ka3 Ba8 70. Ka4 Bb7 71. Ka5 Ba8 72. Kb6 h5 73. Ka5 Bb7 74. Ka4 Ba8 75. Ka3 Bb7 76. Ka2 Ba8 77. Kb1 Bb7 78. Kc2 Ba8 79. Kd3 Bb7 80. Rf1 Ba8 81. Re1 Bb7 82. Rd1 Ba8 83. Kc2 Bb7 84. Kb1 Ba8 85. Ka2 Bb7 86. Ka3 Ba8 87. Ka4 Bb7 88. Ka5 Ba8 89. Kb6 h4 90. Ka5 Bb7 91. Ka4 Ba8 92. Ka3 Bb7 93. Ka2 Ba8 94. Kb1 Bb7 95. Kc2 Ba8 96. Kd3 Bb7 97. Rf1 Ba8 98. Re1 Bb7 99. Rd1 Ba8 100. Kc2 Bb7 101. Kb1 Ba8 102. Ka2 Bb7 103. Ka3 Ba8 104. Ka4 Bb7 105. Ka5 Ba8 106. Kb6 h3 107. Ka5 Bb7 108. Ka4 Ba8 109. Ka3 Bb7 110. Ka2 Ba8 111. Kb1 Bb7 112. Kc2 Ba8 113. Kd3 Bb7 114. Rf1 Ba8 115. Re1 Bb7 116. Rd1 Ba8 117. Kc2 Bb7 118. Kb1 Ba8 119. Ka2 Bb7 120. Ka3 Ba8 121. Ka4 Bb7 122. Ka5 Ba8 123. Kb6 h6 124. Ka5 Bb7 125. Ka4 Ba8 126. Ka3 Bb7 127. Ka2 Ba8 128. Kb1 Bb7 129. Kc2 Ba8 130. Kd3 Bb7  131. Rf1 Ba8 132. Re1 Bb7 133. Rd1 Ba8 134. Kc2 Bb7 135. Kb1 Ba8 136. Ka2 Bb7 137. Ka3 Ba8 138. Ka4 Bb7 139. Ka5 Ba8 140. Kb6 h5 141. Ka5 Bb7 142. Ka4 Ba8 143. Ka3 Bb7 144. Ka2 Ba8 145. Kb1 Bb7 146. Kc2 Ba8 147. Kd3 Bb7 148. Rf1 Ba8 149. Re1 Bb7 150. Rd1 Ba8 151. Kc2 Bb7 152. Kb1 Ba8 153. Ka2 Bb7 154. Ka3 Ba8 155. Ka4 Bb7 156. Ka5 Ba8 157. Kb6 h4 158. Ka5 Bb7 159. Ka4 Ba8 160. Ka3 Bb7 161. Ka2 Ba8 162. Kb1 Bb7 163. Kc2 Ba8 164. Kd3 Bb7 165. Rf1 Ba8 166. Re1 Bb7 167. Rd1 Ba8 168. Kc2 Bb7 169. Kb1 Ba8 170. Ka2 Bb7 171. Ka3 Ba8 172. Ka4 Bb7 173. Ka5 Ba8 174. Kb6 h1=Q 175. Rxh1 Bg7 176. Rd1+ Bd4 177. Ka5 Bb7 178. Ka4 Ba8 179. Ka3 Bb7 180. Ka2 Ba8 181. Kb1 Bb7 182. Kc2 Ba8 183. Kd3 Bb7 184. Rf1 Ba8 185. Re1 Bb7 186. Rd1 Ba8 187. Kc2 Bb7 188. Kb1 Ba8 189. Ka2 Bb7 190. Ka3 Ba8 191. Ka4 Bb7 192. Ka5 Ba8 193. Kb6 h2 194. Ka5 Bb7 195. Ka4 Ba8 196. Ka3 Bb7 197. Ka2 Ba8 198. Kb1 Bb7 199. Kc2 Ba8 200. Kd3 Bb7 201. Rf1 Ba8 202. Re1 Bb7 203. Rd1 Ba8 204. Kc2 Bb7 205. Kb1 Ba8 206. Ka2 Bb7 207. Ka3 Ba8 208. Ka4 Bb7 209. Ka5 Ba8 210. Kb6 h3 211. Ka5 Bb7 212. Ka4 Ba8 213. Ka3 Bb7 214. Ka2 Ba8 215. Kb1 Bb7 216. Kc2 Ba8 217. Kd3 Bb7 218. Rf1 Ba8 219. Re1 Bb7 220. Rd1 Ba8 221. Kc2 Bb7 222. Kb1 Ba8 223. Ka2 Bb7 224. Ka3 Ba8 225. Ka4 Bb7 226. Ka5 Ba8 227. Kb6 h1=Q 228. Rxh1 Bg7 229. Rd1+ Bd4 230. Ka5 Bb7 231. Ka4 Ba8 232. Ka3 Bb7 233. Ka2 Ba8 234. Kb1 Bb7 235. Kc2 Ba8 236. Kd3 Bb7 237. Rf1 Ba8 238. Re1 Bb7 239. Rd1 Ba8 240. Kc2 Bb7 241. Kb1 Ba8 242. Ka2 Bb7 243. Ka3 Ba8 244. Ka4 Bb7 245. Ka5 Ba8 246. Kb6 h2 247. Ka5 Bb7 248. Ka4 Ba8 249. Ka3 Bb7 250. Ka2 Ba8 251. Kb1 Bb7 252. Kc2 Ba8 253. Kd3 Bb7 254. Rf1 Ba8 255. Re1 Bb7 256. Rd1 Ba8 257. Kc2 Bb7 258. Kb1 Ba8 259. Ka2 Bb7 260. Ka3 Ba8 261. Ka4 Bb7 262. Ka5 Ba8 263. Kb6 h1=Q 264. Rxh1 Bg7 265. Rd1+ Bd4 266. Ka5 Bb7 267. Ka4 Ba8 268. Ka3 Bb7 269. Ka2 Ba8 270. Kb1 Bb7 271. Kc2 Ba8 272. Kd3 Bb7 273. Rf1 Ba8 274. Re1 Bb7 275. Rd1 Ba8 276. Kc2 Bb7 277. Kb1 Ba8 278. Ka2 Bb7 279. Ka3 Ba8 280. Ka4 Bb7 281. Ka5 Ba8 282. Kb6 Bb7 283. Kxb7 b1=Q 284. Rxb1 Be5 285. Rd1+ Bd4 286. Rxd4+ cxd4 287. Kb6 d3 288. a8=Q Rxb8+ 289. Qxb8 dxe2 290. Qxd8#

Lastly, if you allow any amount of illegal material, with no first/last rank pawns and one king per side of course, here is a mate in 415 that is an extension of Blathy's above mate in 290.
 [FEN "bBrb1B2/P1n1r1bp/pKp1P2p/2pk1P1p/5P1p/1P2pP1p/1pP1P2p/1R5n w - - 0 1"]

1. Rd1+ Bd4 2. c4+ Kd6 3. Rxh1 Bc3 4. Rd1+ Bd4 5. Ka5 Bb7 6. Ka4 Ba8 7. Ka3 Bb7 8. Ka2 Ba8 9. Kb1 Bb7 10. Kc2 Ba8 11. Kd3 Bb7 12. Rh1 Ba8 13. Rf1 Bb7 14. Rd1 Ba8 15. Kc2 Bb7 16. Kb1 Ba8 17. Ka2 Bb7 18. Ka3 Ba8 19. Ka4 Bb7 20. Ka5 Ba8 21. Kb6 h1=Q 22. Rxh1 Bc3 23. Rd1+ Bd4 24. Ka5 Bb7 25. Ka4 Ba8 26. Ka3 Bb7 27. Ka2 Ba8 28. Kb1 Bb7 29. Kc2 Ba8 30. Kd3 Bb7 31. Rh1 Ba8 32. Rf1 Bb7 33. Rd1 Ba8 34. Kc2 Bb7 35. Kb1 Ba8 36. Ka2 Bb7 37. Ka3 Ba8 38. Ka4 Bb7 39. Ka5 Ba8 40. Kb6 h2 41. Ka5 Bb7 42. Ka4 Ba8 43. Ka3 Bb7 44. Ka2 Ba8 45. Kb1 Bb7 46. Kc2 Ba8 47. Kd3 Bb7 48. Rh1 Ba8 49. Rf1 Bb7 50. Rd1 Ba8 51. Kc2 Bb7 52. Kb1 Ba8 53. Ka2 Bb7 54. Ka3 Ba8 55. Ka4 Bb7 56. Ka5 Ba8 57. Kb6 h3 58. Ka5 Bb7 59. Ka4 Ba8 60. Ka3 Bb7 61. Ka2 Ba8 62. Kb1 Bb7 63. Kc2 Ba8 64. Kd3 Bb7 65. Rh1 Ba8 66. Rf1 Bb7 67. Rd1 Ba8 68. Kc2 Bb7 69. Kb1 Ba8 70. Ka2 Bb7 71. Ka3 Ba8 72. Ka4 Bb7 73. Ka5 Ba8 74. Kb6 h4 75. Ka5 Bb7 76. Ka4 Ba8 77. Ka3 Bb7 78. Ka2 Ba8 79. Kb1 Bb7 80. Kc2 Ba8 81. Kd3 Bb7 82. Rh1 Ba8 83. Rf1 Bb7 84. Rd1 Ba8 85. Kc2 Bb7 86. Kb1 Ba8 87. Ka2 Bb7 88. Ka3 Ba8 89. Ka4 Bb7 90. Ka5 Ba8 91. Kb6 h5 92. Ka5 Bb7 93. Ka4 Ba8 94. Ka3 Bb7 95. Ka2 Ba8 96. Kb1 Bb7 97. Kc2 Ba8 98. Kd3 Bb7 99. Rh1 Ba8 100. Rf1 Bb7 101. Rd1 Ba8 102. Kc2 Bb7 103. Kb1 Ba8 104. Ka2 Bb7 105. Ka3 Ba8 106. Ka4 Bb7 107. Ka5 Ba8 108. Kb6 h6 109. Ka5 Bb7 110. Ka4 Ba8 111. Ka3 Bb7 112. Ka2 Ba8  113. Kb1 Bb7 114. Kc2 Ba8 115. Kd3 Bb7 116. Rh1 Ba8 117. Rf1 Bb7 118. Rd1 Ba8 119. Kc2 Bb7 120. Kb1 Ba8 121. Ka2 Bb7 122. Ka3 Ba8 123. Ka4 Bb7 124. Ka5 Ba8 125. Kb6 h1=Q 126. Rxh1 Bc3 127. Rd1+ Bd4 128. Ka5 Bb7 129. Ka4 Ba8 130. Ka3 Bb7 131. Ka2 Ba8 132. Kb1 Bb7 133. Kc2 Ba8 134. Kd3 Bb7 135. Rh1 Ba8 136. Rf1 Bb7 137. Rd1 Ba8 138. Kc2 Bb7 139. Kb1 Ba8 140. Ka2 Bb7 141. Ka3 Ba8 142. Ka4 Bb7 143. Ka5 Ba8 144. Kb6 h2 145. Ka5 Bb7 146. Ka4 Ba8 147. Ka3 Bb7 148. Ka2 Ba8 149. Kb1 Bb7 150. Kc2 Ba8 151. Kd3 Bb7 152. Rh1 Ba8 153. Rf1 Bb7 154. Rd1 Ba8 155. Kc2 Bb7 156. Kb1 Ba8 157. Ka2 Bb7 158. Ka3 Ba8 159. Ka4 Bb7 160. Ka5 Ba8 161. Kb6 h3 162. Ka5 Bb7 163. Ka4 Ba8 164. Ka3 Bb7 165. Ka2 Ba8 166. Kb1 Bb7 167. Kc2 Ba8 168. Kd3 Bb7 169. Rh1 Ba8 170. Rf1 Bb7 171. Rd1 Ba8 172. Kc2 Bb7 173. Kb1 Ba8 174. Ka2 Bb7 175. Ka3 Ba8 176. Ka4 Bb7 177. Ka5 Ba8 178. Kb6 h4 179. Ka5 Bb7 180. Ka4 Ba8 181. Ka3 Bb7 182. Ka2 Ba8 183. Kb1 Bb7 184. Kc2 Ba8 185. Kd3 Bb7 186. Rh1 Ba8 187. Rf1 Bb7 188. Rd1 Ba8 189. Kc2 Bb7 190. Kb1 Ba8 191. Ka2 Bb7 192. Ka3 Ba8 193. Ka4 Bb7 194. Ka5 Ba8 195. Kb6 h5 196. Ka5 Bb7 197. Ka4 Ba8 198. Ka3 Bb7 199. Ka2 Ba8 200. Kb1 Bb7 201. Kc2 Ba8 202. Kd3 Bb7 203. Rh1 Ba8 204. Rf1 Bb7 205. Rd1 Ba8 206. Kc2 Bb7 207. Kb1 Ba8 208. Ka2 Bb7 209. Ka3 Ba8 210. Ka4 Bb7 211. Ka5 Ba8 212. Kb6 h1=Q 213. Rxh1 Bc3 214. Rd1+ Bd4 215. Ka5 Bb7 216. Ka4 Ba8 217. Ka3 Bb7 218. Ka2 Ba8 219. Kb1 Bb7 220. Kc2 Ba8 221. Kd3 Bb7 222. Rh1 Ba8 223. Rf1 Bb7 224. Rd1 Ba8 225. Kc2 Bb7 226. Kb1 Ba8 227. Ka2 Bb7 228. Ka3 Ba8 229. Ka4 Bb7 230. Ka5 Ba8 231. Kb6 h2 232. Ka5 Bb7 233. Ka4 Ba8 234. Ka3 Bb7 235. Ka2 Ba8 236. Kb1 Bb7 237. Kc2 Ba8 238. Kd3 Bb7 239. Rh1 Ba8 240. Rf1 Bb7 241. Rd1 Ba8 242. Kc2 Bb7 243. Kb1 Ba8 244. Ka2 Bb7 245. Ka3 Ba8 246. Ka4 Bb7 247. Ka5 Ba8 248. Kb6 h3 249. Ka5 Bb7 250. Ka4 Ba8 251. Ka3 Bb7 252. Ka2 Ba8 253. Kb1 Bb7 254. Kc2 Ba8 255. Kd3 Bb7 256. Rh1 Ba8 257. Rf1 Bb7 258. Rd1 Ba8 259. Kc2 Bb7 260. Kb1 Ba8 261. Ka2 Bb7 262. Ka3 Ba8 263. Ka4 Bb7 264. Ka5 Ba8 265. Kb6 h4 266. Ka5 Bb7 267. Ka4 Ba8 268. Ka3 Bb7 269. Ka2 Ba8 270. Kb1 Bb7 271. Kc2 Ba8 272. Kd3 Bb7 273. Rh1 Ba8 274. Rf1 Bb7 275. Rd1 Ba8 276. Kc2 Bb7 277. Kb1 Ba8 278. Ka2 Bb7 279. Ka3 Ba8 280. Ka4 Bb7 281. Ka5 Ba8 282. Kb6 h1=Q 283. Rxh1 Bc3 284. Rd1+ Bd4 285. Ka5 Bb7 286. Ka4 Ba8 287. Ka3 Bb7 288. Ka2 Ba8 289. Kb1 Bb7 290. Kc2 Ba8 291. Kd3 Bb7 292. Rh1 Ba8 293. Rf1 Bb7 294. Rd1 Ba8 295. Kc2 Bb7 296. Kb1 Ba8 297. Ka2 Bb7 298. Ka3 Ba8 299. Ka4 Bb7 300. Ka5 Ba8 301. Kb6 h2 302. Ka5 Bb7 303. Ka4 Ba8 304. Ka3 Bb7 305. Ka2 Ba8 306. Kb1 Bb7 307. Kc2 Ba8 308. Kd3 Bb7 309. Rh1 Ba8 310. Rf1 Bb7 311. Rd1 Ba8 312. Kc2 Bb7 313. Kb1 Ba8 314. Ka2 Bb7 315. Ka3 Ba8 316. Ka4 Bb7 317. Ka5 Ba8 318. Kb6 h3 319. Ka5 Bb7 320. Ka4 Ba8 321. Ka3 Bb7 322. Ka2 Ba8 323. Kb1 Bb7 324. Kc2 Ba8 325. Kd3 Bb7 326. Rh1 Ba8 327. Rf1 Bb7 328. Rd1 Ba8 329. Kc2 Bb7 330. Kb1 Ba8 331. Ka2 Bb7 332. Ka3 Ba8 333. Ka4 Bb7 334. Ka5 Ba8 335. Kb6 h1=Q 336. Rxh1 Bc3 337. Rd1+ Bd4 338. Ka5 Bb7 339. Ka4 Ba8 340. Ka3 Bb7 341. Ka2 Ba8 342. Kb1 Bb7 343. Kc2 Ba8 344. Kd3 Bb7 345. Rh1 Ba8 346. Rf1 Bb7 347. Rd1 Ba8 348. Kc2 Bb7 349. Kb1 Ba8 350. Ka2 Bb7 351. Ka3 Ba8 352. Ka4 Bb7 353. Ka5 Ba8 354. Kb6 h2 355. Ka5 Bb7 356. Ka4 Ba8 357. Ka3 Bb7 358. Ka2 Ba8 359. Kb1 Bb7 360. Kc2 Ba8 361. Kd3 Bb7 362. Rh1 Ba8 363. Rf1 Bb7 364. Rd1 Ba8 365. Kc2 Bb7 366. Kb1 Ba8 367. Ka2 Bb7 368. Ka3 Ba8 369. Ka4 Bb7 370. Ka5 Ba8 371. Kb6 h1=Q 372. Rxh1 Bc3 373. Rd1+ Bd4 374. Ka5 Bb7 375. Ka4 Ba8 376. Ka3 Bb7 377. Ka2 Ba8 378. Kb1 Bb7 379. Kc2 Ba8 380. Kd3 Bb7 381. Rh1 Ba8 382. Rf1 Bb7 383. Rd1 Ba8 384. Kc2 Bb7 385. Kb1 Ba8 386. Ka2 Bb7 387. Ka3 Ba8 388. Ka4 Bb7 389. Ka5 Ba8 390. Kb6 a5 391. Kxa5 Bb7 392. Ka4 Ba8 393. Ka3 Bb7 394. Ka2 Ba8 395. Kb1 Bb7 396. Kc2 Ba8 397. Kd3 Bb7 398. Rh1 Ba8 399. Rf1 Bb7 400. Rd1 Ba8 401. Kc2 Bb7 402. Kb1 Ba8 403. Ka2 Bb7 404. Ka3 Ba8 405. Ka4 Bb7 406. Ka5 Ba8 407. Kb6 Bb7 408. Kxb7 b1=Q 409. Rxb1 Be5 410. Rd1+ Bd4 411. Rxd4+ cxd4 412. Kb6 d3 413. a8=Q Rxb8+ 414. Qxb8 d2 415. Qxd8#


Promoting to Rook or Bishop Is there  any chess position where the most correct move would be promoting a pawn on the 7th or 2nd rank to a Rook or Bishop since the queen can perform both their moves.

For rook is typical this one:

W: Kh8 Re3, B:Kg4 Pf2

White to move can't hold.

Re4 Kg5 Re5 Kg6 Re6 Kf7 Re5! f1R!! (queening runs to Rf5 with stalemate). Rh5 Kg6  0-1


How do you document your opening repertoire on a mac? I have an opening repertoire which I play consistently. My problem, however, is that occasionally I will find holes in my repertoire: main line variations for which I have zero prep. I'd like to make my repertoire air-tight. As in, I would like to fill these gaps in my knowledge of theory.
My Idea is to thoroughly document, and scribe my repertoire. In doing this, I should clearly be able to see where my knowledge of theory is lacking and devote extra effort into learning those lines/ middlegame plans/ structures etc.
The problem, however, is that I can't find any software which would allow me to do precisely this. My computer is a mac, and so I cant use programs like chessbase or bookup. I have attempted to write out all the lines in a word processor, but it becomes extremely difficult to keep my lines organized, and I also cannot easily see the position on a board.
If anyone knows of a good solution I would be ecstatic to hear.

A lichess study would be a good way to do this.


Anand - Gelfand 12th game in World Chess championship 2012 I have been following 12th game in World Chess championship 2012, and I just could not understand why a draw was offered.

Is it that they can see 10 or more moves ahead and think of the ending or is it that they want to play it safe and fight another day?

There are two levels at which this can be answered, I suppose: what were the personal motivations for offering/agreeing a draw, and what were the objective features of the position that grounded the decision? I think you're asking mostly after the second, but I've read many comments lately voicing frustration with agreed draws in this match, so I hope you don't mind me giving an answer that speaks to the first level as well.

First off, the position after 21 moves was as follows:

[fen "r2r4/4bkpp/5p2/p1Bbp3/7P/1P1P1N2/P4PP1/R1R3K1 w - - 0 1"]

1. Bxe7 1/2-1/2

Here Anand played 22. Bxe7 and offered a draw, despite being a pawn up in material and having a significant time advantage (with still 18 moves left to the time control after what would have been Gelfand's obligatory recapture 22... Kxe7).

In the post-game press conference, Anand was asked if he considered trying to play on his time advantage at the end, using it to hopefully induce errors on Gelfand's part. His reply:

  "After Bxe7 Kxe7, black's play is very easy. I didn't see any point in dragging it on from there."

In reply to a later question, Anand elaborated further on this and other agreed draws from the match:

  "We only draw when it's obvious, at least to us, that the game is going nowhere."

One journalist spoke up for the amateur spectators, in the spirit of your question, asking why the contestants couldn't play out some more moves for the benefit of those who don't see why this position is a draw. Gelfand fielded that question, answering:

  "First and foremost, here, we are competing in the match for the crown. We are not here purely to entertain spectators. Second thing, there are about a dozen professional, highly-qualified commentators, and with a little bit of effort they could explain to the thousands of spectators elsewhere the nuances of the game."

I think this is a fair point; his and Anand's job right now is to make chess decisions based on personal competitive interests, and not to explain the games either verbally afterward or by playing on in a position each recognizes as clearly equal, and offering no realistic prospects of an advantage for his side.

Which brings me to the second level of your question. I am not a highly-qualified professional, of course, but I think the concrete factors leading to Anand's draw offer are that, though he is a pawn up, it is a weak isolated pawn on d3, one which is hard to make use of, or to be rid of by advancing to d4. And his 2-to-1 pawn majority on the queenside is very immobile, with Gelfand's bishop and rooks having plenty of space and open lines to operate with and restrict Anand's pawns. Furthermore, Gelfand has not a single structural weakness in his position. In a nutshell, this is why Anand's extra pawn doesn't mean very much, and why Gelfand's play is easy enough in this position that Anand didn't consider the time factor to be terribly important.


Does FIDE or USCF allow ICCF type numerical notation instead of the so called algebraic? ICCF uses pure numerical notation counting each square by row and column  eg  11 to 88.  So Pd4 often written just d4 -  would be 2224 so there can never be any confusion should two pieces be able to move to the same square.

If One used that notation in an OTB tournament would FIDE accept it or would that be a problem?

Neither appears to allow numerical notation.

FIDE requires algebraic notation.

  Article 8: The recording of the moves
  8.1.1

  In the course of play each player is required to record his own moves
  and those of his opponent in the correct manner, move after move, as
  clearly and legibly as possible, in the algebraic notation (Appendix
  C), on the ‘scoresheet’ prescribed for the competition.

The USCF prefers algebraic, but also permits descriptive or "computer notation".

  The Recording of Games15A. Manner of keeping score.In the course of play each player is required to record the game (both the player’s
  and the opponent’s moves), move after move, as clearly and legibly as
  possible, on the scoresheetprescribed for the competition. Algebraic
  notationis standard, but descriptive or computer notation is
  permitted.

I cannot find a definition for "computer notation" in their rules.


Importance of memory in chess I know that creativity and calculating skill are the paramount characteristics for chess success, with luck basically non-existent, but just how important is memory?  I suppose that pattern recognition, an important ability, is just a subliminal form of memory, but I'm talking about opening line and end game principles.   Even when I think I know them I find that I'm often compromised by forgetting significant elements of same during a game.   Would that necessarily doom one to mediocrity?

Even after mugging up infinite opening lines and countless endgame positions, we can still be mediocre chess players, if we don't understand the underlying principles and strategies. Human memory is limited. You are bound to forget opening lines. Trying to play by memory alone beyond move 5-10 can lead to disastrous consequences.

Chess has so many combinations that even if you know 100 variations of a particular opening, the opponent will play the 101st one. Now, the best line of defence is to think something like - "I haven't seen this variation before. But I have seen similar ones. In those, the motivation was to gain a powerful pawn center. Here, my opponent is trying to dismantle my pawn centre. What should I do? He is doing so by compromising his own pawn structure. So should I go for the pawn exchange? By the way, his last pawn move leaves his knight unguarded. Shall I attack it?"


Danish Gambit - What next? I was studying the Danish Gambit recently. The Wikipedia page about Danish Gambit listed the first moves as: 1. e4 e5 2. d4 exd4 3. c3 dxc3 4. Nxc3...

[FEN " "]
1. e4 e5 2. d4 exd4 3. c3 dxc3 4. Nxc3

I am a beginner and I didn't what to do after. The page itself listed a few variations.

4...d6 5.Bc4 Nc6 6.Nf3
4...Bc5 5.Bc4 Nc6 6.Nf3
4...Nc6 5.Bc4 and 6.Nf3
4...Bb4 5.Bc4

But I could not understand them (I mean, I couldn't make out the use of making those particular moves). Could anyone help me to decode the underlying tactics of making such moves?

Well, both sides are trying to develop their pieces.

For White, Bc4 develops his bishop and points at the important f7 square. Nf3 develops his knight and controls d4 and e5. He could also eventually now play Ng5 aiming again at f7.

Black also wants to develop his pieces. ...Nf6 is often one of the first developing moves Black makes, clearing out pieces from his kingside back rank so that he can castle, but right now 4...Nf6 would be silly because White would just play 5.e5 and Black's knight would have nowhere to go except back to g8. So other ideas of his include

4...d6, controlling e5 to make ...Nf6 possible, and also clearing space for his light-squared bishop to develop
4...Bc5, developing his bishop and taking one step towards castling kingside
4...Nc6, developing his knight and controlling the central squares d4 and e5
4...Bb4, with some of the same ideas as ...Bc5, also creating a pin so that White's knight can't move and e4 is less defended.

No crazy tactics, just getting your pieces all out there so you can start fighting.


Is a King, Rook and Knight vs King and Knight end game generally a win for the player with the rook? I ended up struggling quite a bit to finish off this position against a better player (I had the knight) and I'm pretty sure he did not play optimally. I've not found much info of this end game. Is a King, Rook and Knight vs King and Knight end game generally a win for the player with the rook?

King + Rook + Knight versus King + Knight. Win? Yes!

My spontaneous thought is to win in two stages.

Catch and win the enemy knight or exchange knights.
Checkmate the enemy king

The first stage should be achieved by hunting down the enemy knight. The second stage is a K+R vs K checkmate.


On Lichess, how do you promote to a rook with algebraic notation? I am a blind chess player on Lichess. I came across a position in which I wanted to promote to a rook. I learned that you can promote by writing like this:
a8=n // promote the pawn at a8 to a knight.

Thus, I modified it to this:
b8 = r // promote the pawn at b8 to a roke.

The error it gives me is: "Envilate move."
I'm not sure what I did wrong. How is it done?
Here is the link to the game:
https://lichess.org/QlZNv9I8
It might look stubid because I wasn't playing the game.

I figured out what is wrong. To promote a pawn to another piece, I need to first type the letter in which the pawn is, followed by the position I want the pawn to go, and lastly the equal sign with the piece I want to promote to.
Here is an example:
"Promote a pawn to a knight"
ee8=n "promote a pawn to a knight"

Here is how it works.
My pawn is at the letter e and I want the pawn to go to e8. So I typed:
ee8

The pawn should be a knight that is where =n came from.
Again here is the algebraic equation to use:
ee8=n


What was it that AlphaZero did that dazzled experts? Wired magazine recently said

  Most remarkably, AlphaZero uncovered new approaches to the game that
  dazzled chess experts.

Just what was unique about alpha zero that was so dazzling?

I could find nothing that would support that statement beyond that it taught itself in a day. This is speculation, but I believe it explains that line in the article.

After researching the author, I found that he is a technology writer, who got a Bachelor of Science from the University of Kent, and later a degree in journalism from University of the Arts London. He currently writes for "Wired", and previously wrote for the MIT Technology Review. Despite that, I could not find a FIDE rating from when he lived in Europe, nor a USCF rating now that he lives in Cambridge Massachusetts.

I get the sense that it could be a "civilian", meaning a guy, who likes chess, but plays chess very casually, who is trying to write an article, and not really understanding the subject fully. It is akin to watching people on TV try to sound like they know about chess.

I think he was simply using his own words to regurgitate the amazement that we chess players all felt when we heard that AlphaZero taught itself in a day, and already could beat the best program, Stockfish.


What is the highest value of pieces on this particular 6x6 board, without any of them attacking each other? I got a question in school in which I have to get the highest score possible by adding pieces on a 6x6 board like this:

The rules are that they are the same color and may never attack each other, and that pieces on my board must also be on yours in the same position.

Here are the point values:

Queen(D)15 points

Rook(R)15 points

Kings(K)10 points

Bishop(B)=9 points

Knight(H)=5 points

Pawn=0 points

My highest value was 97 by placing 8 bishops.

This was the correct answer with 100 points!


Chess Position Trainer Would anyone know how to set up training in a "random position" with Chess Position Trainer (ver 5.04)?  I know and use its option to train "the variation", but was hoping there would be sort of - "make a move from a randomly chosen position" type of training.
Is there a way to set up a position (middlegame, or an endgame) with Chess Position Trainer without having to go over the whole game?

I have not used Chess Position Trainer, but Chesshero has these capabilities you are looking for. You can do the following:

a) Define the pgns from which to pick the random positions

b) Define the start and end move numbers to pick from (this can be useful for generating middle-game or end-game or opening positions specifically)

c) You can define a blunder threshold, which will be used to give you scores when the move you made is evaluated against an engine

d) You can make it timed as well.


Chess Opening Puzzle App I like chess puzzle apps. But they all focus on the end or middle game.

The reason is clear: In the opening there is no single truth.

But there is some common sense what's good and what's not.

Is there an android app which help me train the best opening moves?

I found some apps for openings, but they work like this: First you need to choose the name of the opening, then you train.

I don't care for the names.

I want to see a chess board and then it is my turn to do the next move.

I don't want to choose a particular opening first.

GM Nigel Davies has a training DVD on opening tricks&traps, I'm sure you will like it.

http://en.chessbase.com/post/nigel-davies-tricks-traps-vol-1

Also, in lichess.org, there are quizzes for finding good development moves in openings, I recommend you to take a look.

By the way, lichess.org can be used by it's Android application, if you don't want to use it from website.


Where can I find a description of the "old" USCF rating system (that was in use through the 1990's)? Where can I find a description of the "old" USCF rating system - not the Harkness system, but the one after that, that was in use up until about 2001 when the "new rating system" was adopted?  I was sure I had a copy of this at one point, but I can no longer locate it.  The US Chess Federation Official Rules of Chess, 3rd Edition, has a high-level overview of the old system, but not all of the specifics.
I am particularly interested in a refresher on how the computation of provisional ratings was done.  Based on my recollection, I think that for a player's first 20 games, their provisional rating was the average of their performance ratings for every game they played, calculated as "opponent's rating +400" for a win, "opponent's rating -400" for a loss, simply "opponent's rating" for a draw.  Then after 20 games, a more Elo-like formula was used, with a fixed K factor of 24 for players rated under 2000, or 18 for players rated 2000 or over.  But, I can't find the actual specifications of this anywhere.  The 3rd Edition rulebook does talk about calculation of provisional ratings in the way I described, but it's not clear to me from reading the high-level description if the "average of performance ratings" based provisional rating was carried through the entire 20 game provisional period, or if it was done for a smaller number of games and then something else was done for the rest of the provisional period.
In any case, I'm sure that finding a copy of the actual description of the rating system (which the 3rd Edition rulebook says can be had "free for the asking from the USCF" - though I am not sure they'd still have any copies available of the specifications for a rating system that hasn't been used in about 20 years.  ;-) ) would answer all of my questions - but I just can't locate it anywhere....

I found this page from Glickman which contains the old provisional formula. That formula is:

R[post] = (N R[pre] + mR[avg] + (W - L)400) / (N+m)
where R[pre] is the player's pre-tournament rating, N is the number of games upon which R[pre] is based, m is the number of games the player completes in the tournament, R[avg] is the average of the opponents' ratings, W is the number of wins, and L is the number of losses. If the player is unrated, set N=0 and R[pre]=0. The final result is rounded to an integer.

The August 1994 report of the USCF Ratings Committee discusses the old provisional system a little. There are some details in there, like how unrated players were initially treated as if they had a rating of 1000 when calculating the ratings of other unrated players.


How are online tactic exercises ratings calculated? There are several sites that give you a tactics rating changing while you solve or fail the exercises.

How do they calculate the problems rating?

Do they use engines to calculate the difficulty or strong players evaluate the difficulty exercise by exercise?

A typical way to do it is to treat puzzles the same as players and rate them based on whether they "win/lose" and the rating of the "opponent"

ChessTempo has a nice explanation here copied below:

  The rating system is inspired by an idea implemented at the Chess
  Tactics Server. CTS treats both problem solvers and the problems as
  opponents with their own ratings and adjusts their rating after
  problem completion (or failure) based on the Glicko ratings system.

  For blitz style games, time taken to solve problems is considered and
  an extra bonus is given for problems solved quickly. The solver gets a
  larger rating increase for problems solved quicker than one standard
  deviation from the average time taken for that problem. For problems
  solved faster than average but less than one standard deviation from
  the average, the normal Glicko based adjustment is made. If the
  problem is solved in slower than average time then the Glicko rating
  adjustment is reduced in proportion to how much slower than average
  the problem was solved. Very slow solutions may result in losing
  rating points, however you will never lose more points than you would
  if you simply got the problem wrong.

  When calculating the average time taken on a problem, only correct
  solutions are included, time taken from incorrect attempts are not
  used to calculate the average time a problem takes to solve.

  It is important to note that after a recent change to time handling in
  blitz mode, time taken after the first move is punished more severely
  than time taken before making your first move. The intention of this
  feature is to discourage 'incremental' guessing to try and solve a
  problem, rewarding users who sum up the situation before making their
  move sequence. Users who prefer to use an incremental approach may
  still do so, however their rating will be lower than users at the same
  level who think out the solutions first.

  Normal Glicko adjustments are made for standard ratings with no
  penalty for time taken. Problems marked incorrect cause the rating of
  that problem to increase and the solver's rating to decrease as
  dictated by normal Glicko rating calculations. Normal Glicko
  adjustments are also made for blitz problems that are marked wrong
  (i.e. the time taken in blitz is ignored when making rating
  adjustments for incorrect problems).


What is the most amazing chess position you have seen? What is the most amazing chess position you have seen?

I have been wanting to ask this question for a while, but feared it would be closed. Since the "Uniquely Satisfying Puzzle" and "What is the most complex chess problem?" questions were not closed, I am going to post it. I hope that this is not voted closed as it is a chance to share some amazing positions.

Please post only one position per answer, but feel free to answer multiple times.

And one last one from a real game. Black to move and win.

 [Date "2003.??.??"]
 [White "Ibrahim"]
 [Black "Ibarra"]
 [FEN "3q4/1p1n1pk1/p1r1p1p1/2P1Pn1p/1P1N1P2/B5rP/5RPK/Q3R3 b - - 0 1"]

 1... Nxd4 $1 2. Kxg3 (2. Qxd4 Rxa3 3. Rd1 Qh4 {is just up a piece.}) 2... Qh4+ $3 3. Kxh4 Nf5+ 4. Kg5 Nf8 5. g4 {and there is no defense to....} Nh7#


How to find the best websites for playing chess? What factors are important when selecting a website to play chess on, including but not limited to features and community?

Note: Since asking for the best chess websites does not fall within the rules for types of questions that are allow on Stack Exchange, I figured I'd attempt to ask basically the same question in a way that will not result in it being closed.

It would depend to a certain extend on what your playing level is and what you want from the experience. Whether you want to play a few games for fun, or if you want to play to improve your game. Also whether you are looking for a free site or are willing to pay a subscription.
I play for fun as well as to improve my game, so I look for a site with a larger number of active players with a good range of rating. And if you are willing to pay the subscription there are sites like ICC and Playchess (hope it isn't against the rules to name sites) that offer very good learning materials like video lectures by very strong players.


How good is 4. d3, the Anti-Berlin? The Berlin Defense is drawish if we reach the Berlin endgame. Yet White doesn't have to go into the endgame, and can instead play 4; d3. However, I hear that the Ruy Lopez is getting less popular in top level because of the Berlin defense. This implies that 4. d3 somehow is not as good compared to the mainlines, such as 3... a6 of the Ruy Lopez. What makes 4. d3 not as good as the Ruy Lopez's mainlines for White?

In the Ruy Lopez White usually wants to play with c3 and d4 to claim the center. If you play d3 instead then you lose a tempo if you still want to go for that plan.
Of course it is not the only possible plan but then the question becomes, if you answer 3...Nf6 with 4.d3, why would you not play the Italian instead where you might get a similar structure after for instance 3.Bc4 Bc5 4.c3 Nf6 5.d3, but arguably keep a bit more flexibility.
Still, 4.d3 against the Berlin is a fine way to play, it just doesn't have a clear benefit over other similar setups.


Chess programs that mimic some amateurs Is there such a thing as a chess program that at random times can vary it's strength of play between say a beginner and an expert? Or maybe a program that a certain random times makes subtle or obvious mistakes?

Of course, and in fact it's very common.

Stockfish

The code for the implementation:

int weakness = 120 - 2 * level;

// Choose best move. For each move score we add two terms, both dependent on
// weakness. One deterministic and bigger for weaker levels, and one random,
// then we choose the move with the resulting highest score.
for (size_t i = 0; i < multiPV; ++i)
{
    // This is our magic formula
    int push = (  weakness * int(topScore - rootMoves[i].score)
                + delta * (rng.rand<unsigned>() % weakness)) / 128;

    if (rootMoves[i].score + push > maxScore)
    {
        maxScore = rootMoves[i].score + push;
        best = rootMoves[i].pv[0];
    }
}

If you ask Stockfish to play weaker chess, it'd randomly choose a weaker move. It does that by drawing from a uniform distribution and linearly relate the level you choose with the random noise (weakness and push in the code).

SmallChess

Other engines adopt other implementations. For example, I prefer a model where I draw a sudden large jump to simulate a gross blunder. The probability depends on the level, and it is related to the number of pieces on the board. When my engine feels it needs to make a blunder, it'd do a quick shallow search. My intention is try to simulate simple tactic errors.


A question about piece development As opening principles say, you shouldn't push too many pawns in the opening. Instead, you should concentrate more on piece development. However, I have good example where it worked the other way around.

[FEN ""]
[Event "?"]
[Site "?"]
[Date "1984"]
[Round "?"]
[White "Emil Joseph Diemer"]
[Black "Tomas Heiling"]
[Result "1-0"]

1.d4 Nf6 2.f3 d6 3.e4 g6 4.g4 Bg7 5.g5 Nfd7 6.f4 c5 7.d5 b5 8.c3 a6 9.h4 Nb6 10.h5 e6 11.h6 Bf8 12.a4 exd5 13.a5 N6d7 14.exd5 Be7 15.c4 f6 16.cxb5 fxg5 17.f5 gxf5 18.Qh5+ Kf8 19.Nf3 Rg8 20.b6 Bb7 21.Nc3 Nf6 22.Nxg5 Nxh5 23.Ne6+ Ke8 24.Nxd8 Ng3 25.Nxb7 Nxh1 26.Bf4 Rg6 27.O-O-O Nf2 28.Re1 Kd7 29.Nb5 Ne4 30.Rxe4 Rg1 31.Re1 Rxf1 32.Rxf1 axb5 33.Rg1 Kc8 34.Nxd6+ Bxd6 35.Bxd6 Nd7 36.Rg8+ Kb7 37.Rg7 Kc8 38.Rxh7 Rxa5 39.b7+ Kxb7 40.Rxd7+ Kc8 41.h7 Ra1+ 42.Kc2 Kxd7 43.h8=Q Kxd6 44.Qd8+ Ke5 45.d6 1-0

Why did Emil win? He didn’t follow opening principles. Instead he did 17 consecutive pawn moves at the beginning.

Several reasons I can see:

In closed positions like you have here, piece development is not as important as in open positions.
To me it seems that black played his King's Indian set up, more or less ignoring what white is playing, which generally is not a good idea.
Black should/could have attacked the center in the beginning more aggressively, thereby gaining space for his piece play. For instance 2. ... d5 would be natural (though likely he would have faced some version of the Blackmar-Diemer gambit). 5.... Nh5 would make any progress for white on the kingside very difficult.
Until around move 16 black played OK and should not be worse. White has gained lots of space, but, if black plays 16... axb5 he does not have any weaknesses, while white's pawns are soon getting weak (a5 and g5 are hanging, ...)
Around move 19, black has a clear advantage and should not have tried to hang on to the extra pawn but instead gone for active play, developing pieces, e.g. 19... Nf6 looks good.
Black might have missed the knight fork on e6 (i.e. might have missed that white is not forced to move the queen after 21...Nf6). Because of this, the whole plan with Bb7, Nf6 loses strength, because it just helps white to develop the knight to c3 (while the bishop on b7 is still not all that great).
28...Kd7 is the final blunder, though admittedly white's Nb5 is not that easy to see

So in summary I'd say: Black played too passively and missed some tactics.


What makes game 5 of the World Championship a draw? I was watching recently the excellent ChessNetwork  commentary of the 5th game of the WCC 2018 between Magnus Carlsen and Fabiano Caruana. The end position looked like this and players shook hands after white played g4:

[FEN "8/5R2/5bp1/3rpk1p/8/4B2P/5PP1/5K2 w - - 0 1"]

There is not much to grip onto on either side for sure, but it doesn't strike me as a draw either. The line I get with Stockfish is not straight forward.

{ [Stockfish 280218 64 POPCNT] 68:+0.00} 1...Ke6 2.Ra7 Rd6 3.Ke2
hxg4 4.hxg4 Rc6 5.f3 Bd8 6.Rg7 Kf6 7.Rg8 Bb6 8.Bh6 Rd6 9.Rf8+ Ke6 10.
Re8+ Kd5 11.Be3 Bd8 12.f4 exf4 13.Bxf4 Re6+ 14.Rxe6 Kxe6 15.Kd3 Kd5
16.Ke3 Be7 17.Kd3 Bb4 18.Ke3 Bc5+ 19.Kf3 Be7 20.Be3 Bd8 21.Bf4 Be7

Is there any simple explanation why this position appears as an obvious draw other than a lack of goals to pursue on both sides?

Computer engines are of little use in positions like this. Still it is a pretty obvious draw, because of:

equal (and very limited) material
pawns on the same side of the board
no weaknesses for either player
active and safe kings

In order to win this, one would have to win material or promote a pawn, neither of which can be forced.


How to resign when my opponent is not at the board? This happened to me yesterday.  It was unreasonable for me to play on, so I was going to resign but my opponent was not at the board.  They probably left the board to watch another game, waiting for my next move.

Question:  What is the correct way to resign if my opponent is not at the board?

I stopped the clock, wrote 1-0 on my scoresheet (I was black), and started resetting the pieces.  But this doesn't strike me as an officially correct thing to do.

I agree with Cleveland that what you did is probably sufficient. One other thing you can always do if you can't find the opponent and are concerned that you might be seen as doing something suspicious is to call the arbiter and announce your resignation to them.


Why can white not mate in this position from Bobby Fischer Teaches Chess (frame 73)? [Event ""]
[Site "https://www.apronus.com/chess/wbeditor.php"]
[SetUp "1"]
[FEN "6rk/p5p1/1q2Q3/3p4/6P1/8/2b2PK1/4R3 w - - 0 1"]

I'm fairly new to anything more than the basics of chess and I'm currently working through Bobby Fischer Teaches Chess. I came across this on page 96 (frame 73) in which he asks whether white can mate in one move.
I was convinced the white rook could move to H1 to mate. However his answer was "white cannot mate". Why is this the case?

The bishop on c2 can be moved to h7 to block the check.


Annotations to Fischer vs Sherwin,1957 I have a Russian translation of Bobby Fischer's My 60 Memorable Games. In the Game 1 (http://www.chessgames.com/perl/chessgame?gid=1008366) in the annotations given after Black's 4. ...Ng8-f6 the author writes that  4...d5 5. Nbd2 Bd6 6. Bg2 Nge7 7. 0-0 0-0 8. Nh4!

[fen ""]
1. e4 c5 2. Nf3 e6 3. d3 Nc6 4. g3 d5 5. Nbd2 Bd6 6. Bg2 Nge7 7. O-O O-O 8. Nh4

results in White's initiative. I think that initiative means creating direct threats to which the opponent must respond immediately. But where is initiative after Nh4? White doesn't seem to create any direct threats at all

You are correct; there is no initiative.  The author is overstating the idea behind Nh4 which is to throw pieces and pawns toward the black king, who is at this point in no danger.

If you put this in a modern chess program it would probably show the position as completely equal.


Are 'Conveyor Belt' Chess variants studied? A 'Conveyor Belt' Chess variant is where rows (And the pieces on them) of the chessboard move left, right, up or down based on different criteria.

I've not seen or heard of a chess variant where rows of a chess board move.

Are these a known and studied variant?

It's not studied to my knowledge. This is my first time hearing of such a variant.


How to gauge someone's chess strength quickly? I plan on teaching a chess class (5 classes in a sequence, each building off the previous, 1 hour each) to high schoolers, with emphasis on applying chess principles to real life. Now, it'll be unproductive to have players of maybe <1200-1300 strength, since they won't quite understand positional and tactical ideas well, and will likely find the class advanced/unproductive.

Given the short time frame, I'd like to somehow assess their playing strength at the beginning of the first class in as short amount of time as possible, so as to make the rest of the sessions most productive for the rest. Any suggestions?

I thought of tactical puzzles, and someone suggested multiple choice format for guess the move, but both will require a good 10 minutes for the students to have a good chance at getting them right.

Perhaps show them positions and ask them to assess them and analyze the various salient features (i.e., king safety, piece mobility, central control, weak squares/color complexes, etc.). Naturally, novice players likely won't be able to formulate a cogent response, but if you're looking to identify at least reasonably strong/experienced players, then I would imagine that kind of approach would be more efficient than presenting them with tactical puzzles.

Tactical puzzles are also slightly scattershot; a strong player can occasionally overlook a tactic, but classic positional motifs are typically readily apparent (as long as the positions you select aren't either overly subtle or purely tactical in nature). I wouldn't expect them to formulate concrete positional plans on the spot and in a short amount of time, but I think the mere ability to identify positional imbalances is a sufficient indicator of some chess skill.

I think you could present a few tactical puzzles as well, as long as they comprise common motifs and don't require overly long combinations. Puzzles that would take ten minutes strikes me as excessive. As an indicator of playing strength, the (in)ability to solve a few fairly simple puzzles in a short amount of time would be relatively conclusive. If the puzzles are short, you can also administer more of them, which is apt to yield more accurate data than the results from a smaller number of more complex puzzles that each require deep thought.


How is this stalemate? My friend played this game as white and wants to know how this is a stalemate. I do not know much about chess and both of us would like to know more about this rule.

k7/2Q5/8/P2P4/1R6/8/2P3PP/6K1 w - - 0 1

1.Rb6 1/2-1/2

Stalemate is defined as the player's whose turn it is to not be in check, & cannot make a legal move (black's only piece, the king, can only move to squares where it will be in check, which is illegal).

By playing Rb6 (or possibly Rxb6), your friend walked into that exact situation. Essentially, she blocked off all the squares the King could move to, which is stalemate (& the result is a draw). It might have been a mistake, or it could have been the best move given the situation.

Additional discussion beyond the original question

If there was a black queen on b6, your friend capturing (Rxb6) was the best move, because they would have to get out of check. They can capture with the queen, the rook, or the pawn, but all three lead to stalemate (a draw is all they can hope for here). If they try to move the king out of check, black takes their queen and has a tiny advantage going into the endgame.

Interestingly, if there was a black bishop on b6 threatening the king, the best move would be to move the king and give up the queen. A rook plus several pawns will eventually overpower a lone bishop in the endgame.

If your friend captured anything other than a queen or bishop on b6, that was a blunder that forced stalemate from a winning position.

If there was no black piece on b6, your friend also had the game basically won. They could have finished it with:

1.Rb8# (Rook moves to the dark square up and to the left of the Queen, and checkmate)

Another option:

1.Qb8# (Queen moves to the same square, and checkmate) among other moves.

The last two cases are perfect examples of how chess can punish or reward you in one move; you can be totally winning and then end up with what is essentially a tie because you messed up.


What's the point of the full move counter in FEN? For what do you need to know the number of full moves? You still can't recreate every move in the game with FEN anyways, so I don't see the point of the full move counter. Is there any rule that depends on it?

You may want to record a fragment of a real game starting from move number 24, for example. Then you specify the FEN after the first 23 moves and set the full move number to 24.


Is this position with KRP against KBP a draw? I encountered the following position with White to move.

[FEN "6R1/8/3k4/pK6/Pb6/8/8/8 w - - 45 83"]

I see no way for White to win, but am not completely sure. Is it known to be a draw? More generally, is the result for all such positions with head-to-head pawns and rook against bishop known?

This endgame is indeed a draw. You can check positions with 7 or fewer pieces in the Sygyzy tablebases to see if they are a win, a loss, or a draw. If you want the depth to mate for 6 pieces or fewer, use the Shredder database
Given the context, I suppose you would like to know why this is a draw. If White was trying to win, the best option is to take Black’s pawn. Black’s bishop is stuck defending it. If the pawn falls, Black falls with it. White can and will win the pawn.
[FEN "6R1/8/3k4/pK6/Pb6/8/8/8 w - - 0 1"]

1. Ra8 Kd5 2. Rxa5 Bxa5 3. Kxa5 Kc5

The clutch is doing soh leaves White with a major problem. The pawn endgame is a draw! Due to having a rook pawn, White will either be stalemated by the Black king, or Black will get in front of the pawn and be stalemated by White.

[Title "White is stalemated"]
[FEN "8/8/8/K1k5/P7/8/8/8 w - - 0 1"]

1. Ka6 Kc6 2. a5 Kc7 3. Ka7 Kc8 4. a6 Kc7 5. Ka8 Kc8 6. a7 Kc7

[Title "Black is stalemated"]
[FEN "8/8/8/K1k5/P7/8/8/8 w - - 0 1"]

1. Ka6 Kc6 2. Ka5 Kb7 3. Kb5 Ka7 4. a5 Kb7 5. a6+ Ka7 6. Ka5 Kb8 7. Kb6 Ka8 8. a7

If White does not target g the Black pawn, BBlack will merely wait it out. They will just shuffle their bishop around to keep protecting their pawn. The Black king will move around such that the pawn endgame will remain drawn. Eventually, there will be a draw via the 50-move rule or threefold repetition.
For all situations with head-to-head pawns, it seems that most will be won. Moving your position one file over move creates gives a win for White. Therefore, it seems to me that the only drawn positions are ones with rook pawns and a close enough Black king. In other words, there are very few of them.
[FEN "7R/8/4k3/1pK5/1Pb5/8/8/8 w - - 0 1"]

1. Rb8 Bb3 2. Rxb5 Kd7 3. Rb7+ Kc8 4. Re7 Bd1 5. b5 Bf3 6. Rf7 Be4 7. Kb6 Bg6 8. Re7 Kd8 9. Re5 Bc2 10. Kc6 Bb3 11. b6 Ba4+ 12. Kd6 Kc8 13. Re7 Kb8 14. b7 Be8 15. Kc5 Ka7 16. Rxe8 Kxb7 17. Re7+ Kc8 18. Kc6 Kb8 19. Rf7 Ka8 20. Kb6 Kb8 21. Rf8#


Can GMs use computers to beat their opponents? For example, suppose it's game 12 of the Carlsen-Caruana match last year. Caruana has white, and he wants to win before the tiebreaks. Now if instead of Caruana playing white, Stockfish were playing, one can practically guarantee that Stockfish will win the game. Therefore, in principle, Caruana can also win the game, regardless of what opening line Carlsen chooses.

So Caruana can pick an opening by inputting what Carlsen is likely to play to Stockfish. For example, suppose Stockfish plays 1.d4 and Carlsen is likely to respond with 1...Nf6. Caruana can give that to Stockfish and see what Stockfish comes up with. Regardless of what line Carlsen chooses, Stockfish should be able to reach a line that has winning chances. In the same way, this technique would beat well-known drawing lines such as the Petroff or the Berlin. This technique would even work to achieve a win with black, since Stockfish is also very likely to beat Carlsen with black.

Questions: does this scheme work? If so, do human GMs already use it? If so, why aren't GMs aiming to win with black as well as with white?

You pretty much described modern day preparation...

This is exactly what GMs are doing, except that they also try to add some of their own creativity into the process. Nevertheless, the majority of the heavy lifting is done by engines.

However, the process doesn't come close to guaranteeing a win due to the sheer number of possibilities. For example, assume that on each of your opponent's moves, he has 3 good moves to choose from. This means:

After his 1st move, you have to prepare for 3 outcomes.
After his 2nd move, you have to prepare for 9 outcomes (since each of the 3 outcomes for his 1st move then have 3 follow up outcomes when its his turn on the 2nd move).
After his 3rd move, you have to prepare for 27 outcomes.
4th move ==> 81 outcomes.
5th move ==> 243 outcomes.
6th move ==> 729 outcomes.
7th move ==> 2187 outcomes.

You can see where this is going, and this is based on the generous assumption that your opponent only has 3 acceptable choices. After the early stages of the opening, this number is often much higher.

But going off 3 choices, the horrible function for the approx. number of reasonable outcomes is f(x) = 3^x, where x is number of moves your opponent has made. However, GMs often still manage to prepare for 20 moves, which means their opponent has moved 10 times. 3^10 = 59,049. So GMs are clearly very clever at predicting what's going to happen, and have excellent memories, but even this can barely get to 20 moves.


Can the Scotch Game really give White chances to get an opening advantage? If I remember well, Kasparov once said that, besides the Ruy Lopez, the Scotch Game is the only serious attempt for White to get an early advantage in the opening after 1.e4 e5. Is that true?

The Scotch Game begins with:

[FEN ""]
1.e4 e5 2.Nf3 Nc6 3.d4

I'm only a discrete player, and my opening repertoire with White for open games includes Italian Game/2-Knights, 4-Knights ... and King's Gambit, just for fun. :)

I've tried the Scotch Game but perhaps I didn't understand the logic and the strategy behind its main lines, since I managed to win only against beginners that played 3... exd4 4.Nxd4 Nxd4 5.Qxd4.

So, what kind of "advantage" can the Scotch Game provide? And how can White take it in its main lines? And why is it that openings like the Italian or the 4-Knights do not provide any "serious attempt to get an advantage?"

I like your question a lot. Though I don't play either side of any 1. e4 e5 openings, it got me thinking about the motivations behind playing the Scotch Game. Though you were clearly happy with the answer you accepted, I'm adding another answer because I don't personally understand how that one addresses the question as you asked it, and I think some further thoughts might be useful for others who come upon the question. So here's an alternative way of looking at things.

To answer your question, yes, against a peer, the Scotch Game really does offer chances of obtaining an opening advantage; Kasparov's record using it against his peers, including Karpov, is a case in point (even though, yes, he is Kasparov and we are not). The Scotch Game will not lead to an opening advantage against equal play by your opponent, but that is no different than with any opening. For example, that is just as true for the Scotch Gambit which Tony's answer recommends as an alternative. (And, incidentally, if the opponent declines the Scotch Gambit, you can just end up in the Italian Game anyway. If we're dismissing out of hand the "standard positional play" in the Scotch Game as offering no hope for an advantage, as expressed in Tony's answer, then I don't know why we wouldn't do the same for the Italian Game. No reason has been given for dismissing either.)

Regarding Kasparov's assertion that only the Ruy Lopez and the Scotch Game are "serious" attempts at obtaining an opening advantage for white after 1. e4 e5 2. Nf3 Nc6, it is safe to say that he was speaking in terms of what he considered to be a serious attempt where he lived, i.e. the very highest echelon of the chess world. I am of course completely unqualified to confirm or dispute Kasparov's opinion on that matter; judging from the frequency of which openings appear after those moves, it does seem that that is the consensus among top players.

In any case, while I won't compare or contrast the Scotch Game with those "lesser" alternatives, I will try to give you a bit of an answer to your question as to what kind of an advantage white can seek in the Scotch Game. As stated above, I don't typically play either side of this opening, and even if I did, I'm not a strong enough player to really be trusted. So I decided to look up John Emms' introductory book Starting Out: The Scotch Game; the thoughts below come from the beginning of that book, and all opinions expressed here are those of Emms, not myself. (If you find any of this explanation enlightening, then consider it a good advertisement for the rest of his book.)

After 3. d4 exd4, white has induced black to give up the center, and we have this pawn structure:

[FEN "4k3/pppp1ppp/8/8/4P3/8/PPP2PPP/4K3 w - - 0 1"]

This structure is already inherently better for white, with greater control of the center and more space for the pieces. Since black typically wants to avoid 4... Nxd4 5. Qxd4, which centralizes white's queen in a nice way, white often ends up exchanging the knights himself with Nxc6, when black has two choices for recapturing. If ...dxc6 is played, then we have the following pawn structure, which is also typical of the Exchange Variation of the Ruy Lopez.

[FEN "4k3/ppp2ppp/2p5/8/4P3/8/PPP2PPP/4K3 w - - 0 1"]

Here white's structural superiority offers a significant advantage in the long-term. For instance, most king-and-pawn endings in this structure are wins for white, because of the ability to create a passer on the kingside, while black cannot do so on the queenside. Everything's not as simple as that, of course, as black can develop pretty painlessly and so has good short-term prospects; but white's structural advantage is the basis for his optimism.

If black instead recaptures via ...bxc6, then her central control is improved, and ideas of playing ...d5 are in the air. White often pushes with e5, and we have this structure:

[FEN "4k3/p1pp1ppp/2p5/4P3/8/8/PPP2PPP/4K3 w - - 0 1"]

Now white has even more space, and the e5 pawn cramps black's position. Black will try to free her position with a ...d6 or ...f6 pawn break, and white will try to prevent this, or make it as disadvantageous as possible.

In none of these scenarios does white obtain an advantage by force (though again, that's just chess for you), but we see that white has structural pluses which offer hopes for an advantage (especially in the long-term) in the Scotch Game. Here's a review of both Emms' book and a similar one by Gary Lane; if you want more guidance on this opening, that review, at least, is positive about both books.


Why is white's best play Nxd5 here? I'm new to chess. In the position below, lichess analysis says that Nxd5 is the best move for white. But can't black just capture the knight afterwards with his pawn and threaten white's pawn and rook in the top right hand corner after white's knight is dead? What makes Nxd5 the best move here?

 [FEN "r3k3/p5R1/p1p4r/2bbp2p/8/P1N3KN/1P5P/R7 w q - 0 1"]

First, you have to understand that computers sometimes play non-human moves because they see things that humans most times do not. It probably sees threats to the white king based on the black bishop pair.

In this position, white is just lost, and those bishops on d5 and c5 working together are incredibly strong, so trading off one of them is desirable. What makes it a little strange is that it gives black connected passed pawns, but they are hard to maintain, let alone advance, due to the active white rooks, and unfortunate black Ra8, but it still does not change the outcome.

Also, the Ra8 is not lost to Nd5 cd; Rg8 Bf8; Rf1 Ke7, but it does tie black up some, which is another reason that Nd5 was best. It is hard to finish his development.

 [FEN "r3k3/p5R1/p1p4r/2bbp2p/8/P1N3KN/1P5P/R7 w q - 0 1"]

 1. Nxd5 cxd5 2. Rg8+ Bf8 3. Rf1 Ke7 4. Rf5 {with a little counterplay that requires accuracy from black} Rf6! 5. Rxh5 (5. Rxe5? Kf7 6. Rh8 Bd6 7. Rxa8 Bxe5+ 8. Kg2 Bxb2 9. Rxa7 Kg6-+)  Rc8! 6. Rxe5 Kd7!! 7. Rd5 Bd6+ 8. Rxd6+ Rxd6 9. Rg7 Kc6 10. Rxa7 Kb6 {with an easy win from here}


I have an unusual chess set and am seeking advice As suggested, I have reworded my question. Hope this is more appropriate.

Many years ago (circa 1988/89) I had commissioned and made a chess set of key characters from the American Independence (American, French and British figures).

This is a one-off (the casts were broken after use) and is hand crafted/painted, made from solid pewter.

I have a data sheet for the set (albeit photocopy quality) detailing the pieces. This set has never been used so the condition is mint.

I was collecting sets for quite a few years and did intend to display this one but never got round to it.

What I am after is advice from the forum as to what to do? I have stopped playing and collecting a long while ago. It's not that I am not a fan of chess but lack a regular playing partner and work consumes so much of my time (particularly when travelling), I can never seem to get the time to even set them on display on the few boards I have.

Sensible comments appreciated.

Thanks

p.s. for information/interest I have uploaded pictures of the set I have described in this post

Amazon, ebay, and top local online shop in your country


What is it called when opposite colored pawns up against each other? When a white pawn and a black pawn are touching on a file, what is it called?

With the exception of Hans Kmoch's attempt to give it a name, which never caught on (I have never seen anyone else use it anywhere), they really do not have a name that I have even seen.

I probably have seen this referred to mostly as "two opposing pawns", but that is really just English rather than a specific chess term.


Why did GM Kogan play such a bad opening in this 1997 game? [FEN ""]
  [Date "1997"]
  [White "GM Kogan"]
  [Black "IM Watzkin"]
  [StartPly "8"]

  1. Nf3 d5 2. c4 dxc4 3. Na3 a6 4. Nxc4 b5 5. Na5 c5 6. b4 cxb4 7. Qc2

The first four moves are common, but then ... 5. Na5 c5 6. b4 cxb4 7. Qc2

Why would a strong GM purposely go in to an opening that is so bad that it is already lost? After move 7 Stockfish evaluates the position as -1 or something like that.

haha well, I was in inspired mode and played one of the MOST creative games of my career that brought me many compliments from genius creative GM as Benko (that watched the game LIVE) and few others too :-)  Not everybody can appreciate 'creative chess' or rather concrete chess with concrete ideas that created big problems and search for HARMONY (for a pawn gambit!)disturbing opponent's normal DVP, while fighting for big center etc and Josh was also shocked and even after the game didn't really appreciated what happened.. (he was 'too conservative' as a player and I could already feel he will never become a GM...) in one point I was with big edge close to winning, but did the old sin to enjoy the position too much and made a blunder... Greetings from Spain! Arthur www.olalachess.com


Humans against computers Are human ratings also progressing, could humans catch up with computers? (maybe playing against strong computers makes us strong)

Are team of humans able to defeat computers? Is any competition like this going on?

The best computers are much better than the best humans, and if I had to make up numbers I'd guess that they're improving at least ten times as fast as humans are (it's a wild approximation but, more or less, humans are improving by around 2 Elo points a year and computers are improving by around 20 points a year). There's no way humans will catch up.