Question: Can you mate with just a Knight + Bishop?

One of the scenarios I am allowed to study using my Fritz 9's endgame training mode is Knight, Bishop, King vs. lone King.

Interestingly enough, the Fritz 9 tutor doesn't actually provide me with any instruction or tutorial.  I just move around the board unable to mate.  Asking the computer to provide hints doesn't mate, nor does allowing the computer to play against me when I'm the lone king.

Is there a mate possibility for this?  What is it?

Also, for anyone else out there, can someone tell me why Fritz9 won't actually teach me anything?  That is why I bought it. 

 why Fritz9 won't actually teach me anything?

Fritz is good for analysis. If you want a tutor, you may want Chessmaster. 

Is there a mate possibility for this?

 Certainly. But first, ask why you're learning it... probably to learn to coordinate a bishop and knight? In that case, check out this lesson which covers B+N+P vs B+2P and then the B+N mate. If you're focused on only the mate here's a 4-part lesson covering it in detail.

it can take as long as 40 or 60 moves though if defended against properly.

With the worst starting position and perfect defense mate takes 33 moves. But on average, it only takes 15-20 moves. You can make a few mistakes and still win.

Thanks likeforests.

Fritz starts in the following position:

Black:   K on F8

White: K on F6, N on F7 and B on F5.

I searched Fritz's game database and found several games that contained this position, but I never found one ending in checkmate, only in resignations. 

I'll try to add more detail later.

Next, can anyone explain why my Fritz9 endgame training for this scenario doesn't actually show me how to mate this way?? 

I performed a checkmate from that starting position, in 19 moves. You have 50 moves to perform checkmate... so you don't need perfect technique. You just need to slowly take away your opponent's squares and keep forcing him in the right direction, and eventually you'll score checkmate. The real danger is accidently letting him back into the center. You can only afford to make a mistake like that once, or you'll completely blow the win.

I've notated the combination to mate with just a knight and a bishop.

Awesome!  

I have had this endgame come up exactly once, in 30 years of chess play.

Unfortunately, it was an online blitz game. And even though I had JUST been studying this mate, I had only seconds on my clock, and ran out of time before I could do it.

I agree with varelse. I also have only had it come up once but it was many years ago. I have heard it comes up an average of two times per lifetime of a chess player so most people feel it is not worth learning. I think it's probably only worth learning for two reasons. One, to say you won two games in your lifetime in this circumstance, and two, to learn basic chess manuevering/mating  skills.

Yes, Patriot games.

Another one is Queen-versus-rook.

I have had that come up exactly once as well.

But by studying it, it heped me tons, with queen vs queen endgames.

Or queen versus whatever.

And bishop/knight endongs helped me to better use my minor pieces in unison. (Put them on same color, they will control opposite squares.)

Is one of those deals where you can learn one thing better, by practicing something else. Like Daniel-san learning karate, by waxing cars.

not super hard, but also not easy to do if (in 50 moves) if you have not worked on it and solved it at home. by the way does anyone know if the chess.com live games consider K+N+N vs K a draw if your time runs out?

later dudes

I believe I remember reading recently that it is a draw. But I am not 100% positive.

For me I train these KBN vs K endgames on another website. There are techniques to do this (just as you would for a KR vs K endgame). Almost all the time with best play, you can drive the enemy king to a corner of the same colour square as your bishop, but sometimes driving the king to the corner of the opposite colour square first is necessary. One example goes like this.

After the above sequence, mate should be in clear view. You can see that I use my three pieces to set up 'barriers' to the enemy king to confine it to a smaller area. Do not make random checks since those checks can likely let the enemy king escape. It is a bit hard to explain in great detail, but this is one way to deal with such endgames (although I may not have provided the best moves in the above example such as 4...Ke8 when 4...Kc8 is more likely played by a human player). If the enemy king is somewhere in the centre, it will be more difficult, but eventually you can drive him to either the 'correct' corner where mate should be looming ahead, or the more likely 'wrong' corner first where you can slowly create barriers to drive him to the 'correct' corner.

Okay, I know that 6. Ne7 appears alien since it looks random, until you realise that after the subsequent move 7. Be3, the Black king cannot escape towards the h1 square.

Who is holding on to the two knights? It could be the case where you have the two knights but you run out of time. Of course in that case, the enemy, having only a lone king, does not have sufficient material to checkmate your king, and hence the game is drawn.

Instead, if the side having the bare king runs out of time, it should be a draw on an online Chess.com game, but it is a win on an over-the-board game according to the FIDE rules, since strictly speaking it is possible (although extremely unlikely since mate cannot be forced) to come up with a legal sequence of moves to checkmate the lone king.

If I read your comments correctly did you say the side with the lone king should get a win in an over the board game? I agree that it's possible for two knights to win, even a forced win, because it's possible that the capture move that leaves just two lone knights could end up in a forced mate position. Probably never happen though, but possible.