Two Knights Cannot Force Checkmate
Although there are checkmate positions with two knights against a king, they cannot be forced. Edmar Mednis stated that this inability to force checkmate is "one of the great injustices of chess" (Mednis 1996:40).
Unlike some other theoretically drawn endgames, such as a rook and bishop versus rook, the defender has an easy task in all endings with two knights versus a lone king. He simply has to avoid moving into a position in which he can be checkmated on the next move, and he always has another move available in such situations (Speelman, Tisdall & Wade 1993:11).
Three knights and a king can force checkmate against a lone king within twenty moves (unless the defending king can win one of the knights) (Fine 1941:5–6).
Read more about this topic: Two Knights Endgame
Famous quotes containing the words knights and/or force:
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Poor knights they are which bravely wait
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—Henry David Thoreau (1817–1862)
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—Zora Neale Hurston (1891–1960)