can you mate with a knight , bishop,and a king?

Yes it is. It is fairly difficult though.

Hi - I'm in a game of this sort now. It is possible but hard. Here are some vids and a simulator I found helpful:

http://www.youtube.com/view_play_list?p=E487E88699E4FA8A

These vids are great because they focus more on the underlying skills (piece unity, etc) than on memorization of a technique for a situation that (apparently) rarely arises. For a beginner like me that was helpful.

http://www.chessvideos.tv/endgame-training/bishop-knight-checkmate.php

Agreed. I personally disagree, however, with those expressing the sentiment that it is extremely difficult. I wasn't able to learn it until I watched computer programs modeling some sample checkmating methods. Still, the approach is rather straightforward (JPF917's general description is accurate), but it is long, and therein lies the difficulty. From some positions it can take upwards of 30 moves, and an error along the way can give rise to a draw by the 50-move rule.

Yes and once you learn the technique keep it in mind when you are playing endgames

It is possible...... but if you did that, wouldn't you be cheating? and you might have babies that are forced to serve in the army. Who knows if they will come back?

I used the computer workout feature to try to figure out this mate (before I have tried many many times, always giving up, but recently I finally succeeded) and it was very satisfying to finally be able to do it. This mate actually has occured in a few of my games; rarely of course, but it has happened probably 5+ times.

I used to not believe it when people said that it's nice to learn this mate to know how to coordinate king bishop and knight. I of course figured this could be learned elsewhere, which of course it can, but the way the bishop and knight work together to trap the king is so elegant that I think it did help me indirectly in other areas of the game. Just a little. It's pretty hard to get the pattern, and there's one part where you have to be really precise, but actually it only takes about 1 or 2 hours of strong concentration to at least be able to execute this mate. Of course to keep yourself from forgetting you'd have to practice it too. My problem was just that I'd always give up before then.

I think it is nice to not have to worry about going into a mate that I don't know how to do anymore, no more fearing that situation.

To whoever said it's not extremely difficult, I agree, but when I was trying to figure out how to do it I wouldn't have. The thing is it seems extremely difficult while you first try to figure out and there is a lot of temptation to give up early. But if you keep at it you start to figure out the best way to trap the king, when to play a waiting move and when not to, etc.

Personally I think queen and king vs king and rook is harder, though I figured that one out to. Although it's pretty tough, it's still not as hard as it first seems. I don't think there is any human who could play the mate perfectly (there's lots of computer like queen moves [such as finding the one move with the queen that forces a concession because any other move allows a queen fork after 6 checks, or something]), but as long as you know the plan well it's not that impossible to do it in a decent amount of moves. Again you really have to concentrate and think imaginatively when you're first trying to figure it out.

It's crazy hard until you "get it" and then it's actually pretty easy. 

B + R vs R is just ridiculous, you could easily spend a year trying to "master" it and even R vs Q is pretty hard.  R vs Q against a computer set up to frustrate you is... well impossible for me.  I did do R vs Q a few times against Rybka though (which is easier because it plays "best" moves).

Even B vs R drawing (head for opposite color corner, there is a stalemate) can be difficult if you fall into a lost position.  Pawnless endgames can be very tricky.

That is very true. I don't think I could have ever gotten it down without help from a program. And K+Q vs. K+R is much harder! I still haven't mastered it... even after watching it being done many times.

There are a few I myself don't bother with and won't for a very long time, such as r + b vs r and two knights vs king and pawn (which apparently sometimes wins for the two knights, [even though two knights vs king is a draw] simply because the pawn being there can take out stalemate possibilities!). And there's probably a whole bunch of other ones, like Q + N vs Q, which is usually supposed to be a draw; I know this one from watching a rapid game (on edited video of course) where karpov managed to screw up and lose even though he was an exchange up! He got into the supposedly drawn endgame mentioned above but botched it (as any human would) in severe mutual time pressure.

I continue to feel an urgency to study and master the "winning" endgames like K+Q vs. K+R, for obvious reasons. Other ones I view as drawn endgames, even if they may not be book draws (such as R+B vs. R), and so I wouldn't bother studying those either. It's a compromise. But the K+2N vs. K+P being winnable makes sense to me, although I wouldn't hold out too much hope for myself mating my opponent if I had those two Knights!

I had R+B vs R in a club blitz game (saced his last bishop for my pawn, really surprised me too), and I knew how to win it... but my expert opponent knew a few lesser-known drawing methods and quickly reached something called "lolly's draw" (alghout I don't know how to spell it) which is a certain position... although we each had about a minute left and after proving the defense worked, I was repeating positions when he walked into a mate in one.

During a different game against the same guy I saced my last piece for B+N vs my lone king near the middle of the board when he had just over a minute left on his clock and I said "lets see it"... and he actually did it... I was impressed.

Oh I forgot something. In my case, having "mastered" (for lack of a better word) king bishop and knight mate, only now could I be able to win a key endgame, (also in computer workout) bishop and knight vs rook with 5-6 pawns on both sides of the board, which is supposed to win for the minors. At some point, after a lot of technique (probably like 30 moves), I think black (weaker side) should be able to, as a last effort, force the white to mate with king bishop and knight vs king. That's a lot of work!

But I think it's striking because everyone talks about how the two pieces can outplay the rook, yet it's such a difficult process to win, and requires knowledge of king bishop and knight vs king!

I hadn't considered that as a drawing resource.  If I find myself with rook vs two minors, I'll keep that in mind... to trade off all pawns and as the last resort sacking my rook for the last pawn.

I don't know how often it will come up, but it's something to be aware of.  Thanks.

It's an old video so the audio and visual is poor, but you might be able to take something from this.

http://www.youtube.com/watch?v=wO1_6K9ImVo

It depends on how much time I have on the clock, how much sleep I got last night, and how much I've had to drink, but generally yes.

I used to teach this skill as a basic checkmate, but having had either side (losing or winning) about fifteen times in 50,000 games (and a few chosen for practice), I've decided that it is not high on the list of practical skills.

Bruce Pandolfini's Pandolfini's Endgame Course has the best instruction I've found in book form for learning the techniques and critical fantasy positions.

It's called the "w" maneuvre and I have been mated once with it. K+B+N

mhmm

zugzwang is a big part in a lot of mates, also for bishop and knight vs king.

Here's just a quick example how I mate Chessmaster (from a random position - mate in 31):

It would be really cool if someone could post how he mates with K+Q vs K+R (with slight feedback)