The primary strategy in the endgame is to promote one of one's pawns by advancing it to the eighth rank. The king becomes a very useful piece in the endgame because the threat of checkmate is minimal.
Endgames are classified according to the type of pieces that remain. Some common types of endgames are discussed below.
King and pawn endgames involve only kings and pawns of both sides. Getting a passed pawn is crucial (a passed pawn is one which does not have an opposing pawn on its file or on adjacent files on its way to promotion). An outside passed pawn, a passed pawn on one of the rook files, is particularly deadly. Opposition is an interesting technique that is used to gain an advantage. When two kings are in opposition, they are on the same file with an empty square separating them. The player having the move loses the opposition. They must move their king and allow the opponent's king to advance.
Rook and pawn endgames are often drawn in spite of one side having an extra pawn. The great master Tarrasch[?] once jocularly said "All rook and pawn endings are drawn". Rook endings are probably the deepest and most well studied endgames. Two thumb rules regarding rooks are worth noting:
In Bishop and pawn endgames, the mobility of the bishop is a crucial factor. A bad bishop is one that is hemmed in by pawns of its own color, and has the burden of defending them. Endings with bishops of opposite color are notorious for their drawish character. They are often drawn even when one side has a two pawn advantage.
Knight and pawn endgames feature clever maneuvering by the knights to capture opponent pawns. While a knight is poor at chasing a passed pawn, it is the ideal piece to block a passed pawn.
In Queen and pawn endings, the dominant theme is for the player with more pawns to avoid perpetual check and advance one of his pawns to get a second queen.
Endings with asymmetric piece possession are less common. A bishop is usually worth more than a knight. A bishop and knight are worth roughly a rook and two pawns, and a queen is worth a rook, a minor piece (bishop or knight) and two pawns. Three pawns are often enough to win against a minor piece, but two pawns rarely are.
Endings with no pawns. A queen or a rook (plus king) can easily checkmate a lone king, and a king and queen can win against king and rook. More interestingly, a bishop and knight can checkmate the lone king. Two knights, in general, cannot.
In general, the player with a material advantage tries to exchange pieces and reach the endgame. In the endgame, it is better for the player with more pawns to exchange pieces but not pawns because king and pawn endings are the most easily won. Also, endings with pawns on both sides of the board are much easier to win.
The line between the middlegame[?] and the endgame is often not clear. It may occur gradually or with the quick exchange of a few pairs of pieces.
With the recent growth of computer chess, an interesting development has been the creation of endgame databases which are tables of stored positions calculated by retrograde analysis. A program which incorporates knowledge from such a database is able to play perfect chess on reaching any position in the database.
See chess terminology for definitions of commonly used chess terms.