Editing Checkmate (section)

===King, bishop and knight===
{{Main|Bishop and knight checkmate}}
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Of the basic checkmates, this is the most difficult one to {{chessgloss|forced mate|force}}, because these two pieces cannot form a linear barrier to the enemy king from a distance. Also, the checkmate can be forced only in a corner that the bishop controls.<ref name=speel7 /><ref>{{harvnb|Müller|Lamprecht|2001|p=18}}</ref>

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|+ Checkmates with a bishop and a knight 
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Two basic checkmate positions are shown with a [[bishop (chess)|bishop]] and a [[knight (chess)|knight]], or the [[bishop and knight checkmate]].<ref>{{harvnb|Kurzdorfer|2003|p=155}}</ref> The first position is a checkmate by the bishop, with the black king in the corner. The bishop can be on other squares along the diagonal, the white king and knight have to be on squares that attack g8 and h7. The second position is a checkmate by the knight, with the black king on a side square next to the corner. The knight can be on other squares that check the black king. The white king must be on a square to protect the bishop and cover a square not covered by the knight.

With the side with the bishop and knight to move, checkmate can be forced in at most thirty-three moves from any starting position,<ref>{{harvnb|Müller|Lamprecht|2001|p=19}}</ref> except those in which the defending king is initially [[fork (chess)|forking]] the bishop and knight and it is not possible to defend both. However, the [[Bishop and knight checkmate|mating process]] requires accurate play, since a few errors could result in a [[draw (chess)|draw]] either by the [[fifty-move rule]] or [[stalemate]].

Opinions differ as to whether or not a player should learn this checkmate procedure.  [[James Howell (chess player)|James Howell]] omits the checkmate with two bishops in his book because it rarely occurs but includes the bishop and knight checkmate. Howell says that he has had it three times (always on the defending side) and that it occurs more often than the checkmate with two bishops.<ref>{{harvnb|Howell|1997|p=138}}</ref>  On the other hand, [[Jeremy Silman]] includes the checkmate with two bishops but not the bishop plus knight checkmate because he has had it only once and his friend [[John L. Watson|John Watson]] has never had it.<ref>{{harvnb|Silman|2007|pp=33,188}}</ref> Silman says: "... mastering it would take a significant chunk of time. Should the chess hopeful really spend many of his precious hours he's put aside for chess study learning an endgame he will achieve (at most) only once or twice in his lifetime?"
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'''Avoid stalemate'''
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|After 1.Na3+?, 1...Kc1! draws.
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This position is an example of a stalemate, from the end of a 1966 [[endgame study]] by A. H. Branton. White has just moved 1.Na3+? If Black moves 1...Kc1!, then White must move his bishop to save it because if the bishop is {{chessgloss|captured}}, the position is a draw because of the {{chessgloss|insufficient material}} rule.  But after any bishop move, the position is a stalemate.<ref>{{harvnb|Roycroft|1972|p=246}}</ref>
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