Chess endgame

The endgame (or ending) is the final stage of a chess game which occurs after the middlegame.

The line between the middlegame and the endgame is often not clear, and may occur gradually or with a quick exchange of pieces.

All chess positions with up to seven pieces on the board have been solved by endgame tablebases,[2] so the outcome (win, loss, or draw) of best play by both sides in such positions is known, and endgame textbooks teach this best play.

[3] The former World Chess Champion Alexander Alekhine said, "We cannot define when the middle game ends and the endgame starts.

"[4] Using the standard system for chess piece relative value, Speelman considers that endgames are positions in which each player has thirteen or fewer points in material (not counting the king).

[5] Minev characterizes endgames as positions having four or fewer pieces other than kings and pawns.

[12] Max Euwe and Walter Meiden give these five generalizations: Many endings without pawns have been solved, that is, best play for both sides from any starting position can be determined, and the outcome (win, loss, or draw) is known.

For example, the following are all wins for the side with pieces: See Wikibooks – Chess/The Endgame for a demonstration of the first two checkmates, which are generally taught in textbooks as basic knowledge.

The last two are sometimes taught as basic knowledge as well, although the procedure for mate with bishop and knight is relatively difficult and many tournament players do not know it.

While there is a board position that allows two knights to checkmate a lone king, such requires a careless move by the weaker side to execute.

International Master Cecil Purdy said, "Pawn endings are to chess as putting is to golf."

Unlike most positions, king and pawn endgames can usually be analyzed to a definite conclusion, given enough skill and time.

If the pawn reaches the seventh rank and is supported by its king and knight, it usually promotes and wins.

[26] This position was reached in a game from the 1965 Candidates Tournament between Lajos Portisch and former World Champion Mikhail Tal.

The knight is best suited at an outpost in the center, particularly where it cannot easily be driven away, whereas the bishop is strongest when it can attack targets on both sides of the board or a series of squares of the same color.

[30] Fine and Benko[31] give four conclusions: This is a draw if the defending king is in front of the pawn or sufficiently close.

The defending king can occupy a square in front of the pawn of the opposite color as the bishop and cannot be driven away.

The ability to play these endgames well is a major factor distinguishing masters from amateurs.

A general rule is that if the weaker side's king can get to the queening square of the pawn, the game is a draw and otherwise it is a win, but there are many exceptions.

Siegbert Tarrasch gave the following rules for this case: For a player defending against a pawn on the fifth or even sixth ranks to obtain a draw, even after his king has been forced off the queening square, the following conditions must obtain: The file on which the pawn stands divides the board into two unequal parts.

The defending rook must stand in the longer part and give checks from the flank at the greatest possible distance from the attacking king.

The context of this quote shows it is a comment on the fact that a small advantage in a rook and pawn endgame is less likely to be converted into a win.

Writers Victor Korchnoi,[42] John Emms,[43] and James Howell,[44] attribute the quote to Tartakower, whereas Dvoretsky,[45] Andrew Soltis,[46] Karsten Müller,[47] and Kaufeld & Kern[48] attribute it to Tarrasch.

John Watson attributed to Tarrasch "by legend" and says that statistics do not support the statement.

Human analysts were not able to make a complete analysis before the advent of endgame tablebases.

The difference in material between a rook and a minor piece is about two points or a little less, the equivalent of two pawns.

This was determined using the easier-to-calculate depth-to-conversion method, which assumes that the two sides are aiming respectively to reduce the game to a simpler won ending or to delay that conversion.

If White has bishop and knight, and Black has a rook, the endgame is classified KBNKR.

The full system is a 53-page index that was contained in the book The Best Endings of Capablanca and Fischer.

The code starts with a letter representing the most powerful piece on the board, not counting kings.