2 Knights checkmate every time if the opponent have a blokaded pawn behind a line: e.i. White has the knights the line is a4-b6-c5-d4-e4-f5-g6-h4 (as i recall it).
If no pawn - checkmate is only possible with help from the opponent. If the pawn has advanced further than the line then it depends on where the kings are.
Probably the best I've seen at explaining the K B N vs K endgame is from Yasser Sierawan's "Winning Chess Endings". I just bought that book and am playing through his annotation of the position. Yasser is an excellent teacher. He has the best explanation of the K B B vs K ending I'd ever seen. I never really studied that ending either, but after reading his analysis, it's really easy.
The K B N vs lone K is very difficult. More often than not, you would have to force the lone K into the "wrong" corner (since he'll be very un-cooperative) and then force him along the back row into the "right" corner, where checkmate can be delivered. ("Wrong" corner refers to a corner square NOT controlled by your Bishop).
The biggest problem with trying to force this type of checkmate is that you only have (at most) 50 moves to do it. The slightest screw-up will usually allow your opponent to slip away and eventually invoke the 50 move draw rule.
I believe I read somewhere that, given a worst case starting position (i.e. Lone K in the center, with your K, N and B near the edge of the board), the minimum # of moves required to force mate is somewhere in the 30s, so it's vital that you don't make a mistake in this ending.
Originally posted by TheBloopI'd like to try it as the one time I got that end game OTB, I hadn't a clue what to do. Anybody fancy playing their lone king against my K + B + N?
Probably the best I've seen at explaining the K B N vs K endgame is from Yasser Sierawan's "Winning Chess Endings". I just bought that book and am playing through his annotation of the position. Yasser is an excellent teacher. He has the best explanation of the K B B vs K ending I'd ever seen. I never really studied that ending either, but after rea ...[text shortened]... ce mate is somewhere in the 30s, so it's vital that you don't make a mistake in this ending.
D
At a tournament in Derry I watched this kid (rated bout 1400) outplay an expert level player (rated 2000 +) get into the Knight + Bishop endgame.
Actually the expert player was two pawns down but took the chance that the kid didn't know the ending. He gave his two knights for the two pawns: the gamble paid off, and the game was drawn.
I still remember the look of relief on the expert's face, and the embarrassed look on the young guy's face.
Everyone had gathered to watch the ending.