This allows the player to control squares of both colors, allows the bishop to move freely among the pawns, and helps fix enemy pawns on squares on which they can be attacked by the bishop. In the middlegame, a player with only one bishop should generally place friendly pawns on squares of the color that the bishop cannot move to.
One such example occurs in the position illustrated, which arises from the Ruy Lopez: 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 b5 6.Bb3 Be7 7.d4 d6 8.c3 Bg4 9.h3 !? Bxf3 10.Qxf3 exd4 11.Qg3 g6 12.Bh6 ! A bishop can fork, but opportunities are rarer. Furthermore, on a crowded board a knight has many tactical opportunities to fork two enemy pieces. A knight check cannot be blocked but a bishop check can. On the other hand, in the opening and middlegame a bishop may be hemmed in by pawns of both players, and thus be inferior to a knight which can jump over them. In these situations, the bishop is said to be "dominating" the knight. A bishop can in some situations hinder a knight from moving. The bishop is capable of skewering or pinning a piece, while the knight can do neither. In certain positions a bishop can by itself lose a move (see triangulation and tempo), while a knight can never do so. A bishop and knight can force mate, but with far greater difficulty than two bishops. Two bishops on opposite-colored squares and king can force checkmate against a lone king, whereas two knights cannot. A player possessing a pair of bishops has a strategic weapon in the form of a long-term threat to trade down to an advantageous endgame. In an open endgame, a pair of bishops is decidedly superior to either a bishop and a knight, or two knights. A bishop can easily influence both wings simultaneously, whereas a knight is less capable of doing so. īishops usually gain in relative strength towards the endgame as more pieces are captured and more open lines become available on which they can operate. More experienced players understand the power of the bishop. Less experienced players tend to underrate the bishop compared to the knight because the knight can reach all squares and is more adept at forking. In general, the bishop is slightly stronger than the knight. This means bishops are approximately equal in strength to knights, but depending on the game situation, either may have a distinct advantage.
Knights and bishops are each worth about three pawns. A king and two bishops on opposite-colored squares, however, can force mate. A king and rook can force checkmate against a lone king, whereas a king and bishop cannot. When unobstructed, a rook attacks fourteen squares regardless of position, whereas a bishop attacks no more than thirteen (from one of four center squares) and sometimes as few as seven (from sides and corners). The bishop has access to only half of the squares on the board, whereas all squares of the board are accessible to the rook. See also: Chess piece relative value and The exchange (chess)Ī rook is generally worth about two pawns more than a bishop.