two knights generally have a better chance of forming a drawing fortress against a queen than do two bishops or a bishop and a knight. Compared to a bishop, a knight is often not as good in an endgame. A knight can exert control over only one part of the board at a time and often takes multiple moves to reposition to a new location, which often makes it less suitable in endgames with pawns on both sides of the board. This limitation is less important, however, in endgames with pawns on only one side of the board. Knights are superior to bishops in an endgame if all the pawns are on one side of the board. Furthermore, knights have the advantage of being able to control squares of either color, unlike a lone bishop. Nonetheless, a disadvantage of the knight (compared to the other pieces) is that by itself it cannot lose a move to put the opponent in zugzwang (see triangulation and tempo), while a bishop can. In the position pictured on the right, if the knight is on a white square and it is White's turn to move, White cannot win. Similarly, if the knight were on a black square and it were Black's turn to move, White cannot win. In the other two cases, White would win. If instead of the knight, White had a bishop on either color of square, White would win with either side to move. In an endgame where one side has only a king and a knight while the other side has only a king, the game is a draw since a checkmate is impossible. When a bare king faces a king and two knights, a checkmate can never be ; checkmate can occur only if the opponent commits a blunder by moving their king to a square where it can be checkmated on the next move. Checkmate can be forced with a bishop and knight, however, or with two bishops, even though the bishop and knight are in general about equal in value. Paradoxically, checkmate with two knights sometimes can be forced if the weaker side has a single extra pawn, but this is a curiosity of little practical value (see two knights endgame). Pawnless endgames are a rarity, and if the stronger side has even a single pawn, an extra knight should give them an easy win. A bishop