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49

Is it rude to ask my opponent to resign an online game when they have a lost endgame? Yes, it is rude, although you are in good company. In one Olympiad Victor Korchnoi is alleged to have asked his opponent - "Do you speak English?" When they said "Yes" he replied "Then please resign". I may be misquoting. He may not have said "please" :-) Strictly ...

41

It's quite a fun problem to think about, before getting to the calculation of long variations, try to first spot the key idea needed to crack the problem. Here are the first observations that come to my mind which eventually led me to spot the solution, let's break them down step by step: a) With our bishop eyeing g7 and our doubled pawn formation on g6-g7,...

34

Brian Towers answered the question, but to help you understand why people don't resign, I recommend you watch this lecture by GM Finegold Blunders, with GM Ben Finegold. The gist of it is: Never resign, and look for resources no matter how bad your position is. And when you are winning, don't let your guard down.

33

White to move: [FEN "8/q1P1k3/8/8/8/8/6PP/7K w - - 0 1"] Since my example is rather contrived and artificial, I'll also say that the so-called Lasker trap in the Albin Countergambit gives a more realistic setting, and one where a knight promotion is the best option as early as move 7: [FEN ""] 1.d4 d5 2.c4 e5 3.dxe5 d4 4.e3 \$2 Bb4+ 5.Bd2 dxe3! 6.Bxb4 \$4 ...

33

Yes, mate can be forced in 33 moves from nearly any position, according to Wikipedia. See the standard "w" maneuver cited in that article.

32

In the specific position that you mention, the answer is a resounding no. The king and the knight will defend each other, and white will not be able to force mate. However, the knight is a clumsy piece. If the knight is not positioned perfectly, then the rook will frequently be able to drive the knight to a bad square and deprive it of moves. Eventually, ...

31

I believe your question essentially boils down to the topic of whether it is possible to completely "solve" chess. Wikipedia has an excellent article on the topic which should give you a good overview. To summarise, the number of possible game variations in chess is estimated to be 10^120. This is a staggeringly huge number, for comparison, consider that ...

31

In short, the key idea is to prevent white from playing h2-h3! Bc4 forces the exchange of light square bishops, and thus, sets up Rh3 which blocks the h2 pawn and keeps both the h2 and g4 pawns weak. Concretely, the only piece currently covering h3 is the light squared bishop on f1, so by trading the bishop with Bc4, which white cannot prevent as Bg2 leaves ...

29

It's always rude to ask your opponent to resign. They should resign of their own accord once they're convinced that you're overwhelmingly likely to win the game. In my case, that always meant you'd have to convince me that you knew how to play the endgame in question and that both of us knew how you would win it. If your opponent hasn't resigned yet, it ...

28

I know you're a FIDE Master :), so I suppose you're more interested in this question from a teaching perspective. The simplest way to understand a checkmate with King and Rook vs King is the idea of the rectangle of the opposing king. Consider this position- Here, the Black King is restricted by the White Rook in this giant rectangular area of the ...

27

I will preface this by saying that I'm a 2150 USCF player who has had the same issues that you are struggling with in the past. What I'm about to tell you comes straight from my own experiences playing chess all these years. Don't study or memorize any theory straight up. I find it difficult to retain information like that and the potential for it to be ...

27

This is not a blunder, expected behaviour from the engine. Everything worked as intended. Try to copy the FEN string out, and you'll know. Although the position looked winning, White didn't have enough moves to force checkmate before the 50 moves rule. Stockfish, knowing the position was a dead draw immediately asked for simplification. The position you ...

26

Shirov resigned: the thinking was that despite both sides left with pawns and a knight, the advantage went to Black. Black has an extra pawn and Black's pawn chain is mutually supporting. White is down a pawn and they are split. White's king is buried too deeply in the corner to either prevent a black pawn advance to promotion or to save White's pawns. ...

23

Actually, the bishop and knight mate is not as slippery as it appears. I have checked this on a tablebase program I wrote. On a 10x10 board, the side with the bishop and knight (say white) can force mate in at most 47 moves. White can even force mate on a 16x16 board, in at most 93 moves. I believe mate can be forced on an arbitrarily large even size ...

23

It's probably a trick problem with a promotion to a black knight. Such promotions to the wrong colour are not allowed, and never were. In the official rules it is now specifically pointed out that the new piece has to have the same colour as the promoted pawn. FIDE's laws of chess, Article 3.7 e: When a pawn reaches the rank furthest from its starting ...

23

According to the Lomonosov tablebases, it's mate in 40 for black. While the queen can't force mate by herself, she can force a zugzwang. In this case, when the bishop is forced to move to e8. Then, it's a matter of giving checks until the queen forks the king and bishop. One of the longest variations given is as follows: [FEN "7k/5BpP/3K2P1/8/8/8/8/4q3 w -...

22

Yes it is possible to force mate. There's a phenomenal video explaining the process on chessvideos.tv. If you want to practice the endgame, you can do so on the same site as well.

22

The weaker side needs to keep Knight close to his King in order to achieve draw. There are some special cases where the stronger side wins even in those situations, like when Knight is cornered or pinned in such a way that puts weaker side in zugzwang. If the Knight is far away from the King then the result of the game depends whether or not the defending ...

21

Seven man end game table bases are already available online: http://chessok.com/?p=28049 By the end of 2013 they should be available off line as well. The size is 140 000 gigabytes so there is an obvious problem with copying them. They did not compute 6 white pieces versus 1 king since they decided it was pointless. Interesting fact- the longest forced ...

21

Here's a simpler way to see why it's winning for black: You're right that the queen cannot checkmate the king by itself, but it can stalemate the king [*] (an example pointed out by Ionut Deaconu) and that's all we need here as that would force the bishop to move. Once the bishop moves it's clear that material loss is unavoidable as either the bishop [**] or ...

20

During round 9 of the Istanbul 2012 Chess Olympiads, at the Nakamura-Kramnik table of the USA vs Russia match, we've witnessed another one of those promotions to knight at move 62 by white. The relevant position (white to play): [fen "8/2P1k3/8/8/5p2/5KbB/3pp3/3N4 w - - 1 62"] 1. c8=N+ (1. Kxe2? f3+ 2. Kxf3 Bxc7) We can see here that if 62. Kxe2 then ...

20

I always like to explain this in a visual way. Basic Idea: Keep the bishops together. They form a large net (restricted area) from which the opponent king cannot escape. Step 1: Push Opponent's King To Edge Rank or File Keeping the bishops together and using the king for support, make the restricted area smaller to push the opponent's king back to an ...

20

Is it really possible to checkmate with two knights and king against a king? Theoretically, the checkmate is possible, but you can not do it in practice unless the weaker side allows you to. This is related to a drawback in the way knight moves. There is a mating position with this but no extra tempo to do it in real game. What are the ...

20

There is a very easy way to detect whether King and Pawn endgames are drawn or not. This method I use is a very easy to understand one from Karsten Mueller and Frank Lamprecht's excellent book Secrets of Pawn Endings It concerns key squares and opposition The rule states that if pawn has not reached or crossed the central line (5th rank for White and 4th ...

20

Honestly it's rude to ask your opponent to resign in any position. The one exception may be them deliberately letting their clock run to 0 in a completely lost position, but in this case they're being deliberately malicious and you can't really hope to reason with them. Even though you're absolutely justified in thinking your opponent should resign, that ...

19

There isn't a clear-cut definition of endgame, or a set of criteria where you could draw a line and say "after this move, we have reached the endgame." Quoting Glenn Flear in his excellent book Practical Endgame Play - Beyond the Basics: The word 'endgame' is widely used and generally implies the final phase of the game (however long!), assuming that ...

18

After answering this question, I was reminded of another important situation where underpromotion is necessary: [FEN "8/8/8/8/8/2K5/1p5R/2k5 b - - 0 1"] 1... b1=N+! (1... b1=Q 2. Rh1++) In this position, 1...b1=N+ is the only move to draw. Any other move will allow a quick mate, but after knighting the pawn, black sets up a drawing fortress. While ...

18

In the second link from Wes' answer, the joint work of Yakov Konoval and Marc Bourzutschky is mentioned in passing, though not described at all, so I thought I'd give them a shout out here, as they have done a lot of work in particular 7-man endgames. This includes impressive work on pawnless endings, such as showing that in this position, where it is Black ...

18

This position is a draw with White to move. However, the same position would lead you to win if it was black to move (Zugzwang). The basic theory for you to promote the pawn when the opponent king is having the opposition is you need to have your king in front of your pawn 2 ranks ahead of the pawn, (i.e. if pawn's on e3 King needs to be on e5) (opposition ...

18

Black is winning handily from the diagram position, and has a fairly straightforward strategy going forward: force the b-pawn's advance to b2 with the support of the bishops (starting with 1...Be6 to gain control of the b3 square), and then slowly push for a new queen, making use of the facts that (1) White must always keep guard over b1, and (2) Black has ...

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