mating question

I read somewhere years go that you need 3 knights to force a mate, although I wouldn't like to try. What I don't know is what other combinations can you FORCE mate with?
2 bishops?
3 bishops? (obviously yes if the answer to 2 was yes)
2 bishops and 1 knight?
2 knights and 1 bishop?
2 knights and 2 bishops? (again, an obvious yes if there was a yes before)

I must make it clear that, although I have pondered this question many times before, I am prompted to ask now because I have a game going where I have 2 knights and 2 bishops against my opponents 1 knight. I could in all probability force a pawn promotion (my 3 to his 1), but I would like to practice mating without a rook or queen involved as I think I have never done it. But only if it is possible, I don't want to be wasting my or my opponents time.

So, if you feel you can give me a possible/not possible answer I'd appreciate it. And after 50 moves, when I've given up & promoted a ppawn to win, mmaybe someone will be kind enough to explain how it possible.

with 2 knights and 2 bishops it should certainly be possible to checkmate - i think the minimum is 1 knight and one bishop although i'm fairly sure that requires support from another piece i.e your king or a pawn - i'm sure someone will give you a fuller answer 😵

thanks. I was looking to do it with the minimum number of pieces I could, but support from the king is OK because I should always have one of those left.
Anyone else know any more detail?

You can force a mate with a king, one knight and one bishop (though it takes some serious maneuvering.) Check out this FEN position: 8/8/8/8/4B3/6K1/4N3/7k b - - 1 1. You can also force a mate with a king and two knights: 8/8/8/8/8/6KN/5N2/7k b - - 1 1, or with a king and two bishops: 8/8/8/8/8/5BK1/7B/7k b - - 1 1, although I must admit, while all of these are legal positions, I'm not sure how you could actually get into the last one without avoiding stalemate.

Hope that helps some.

-mike

thanks. I won't read the detail until the game is over, or it would be unfair. I could lose his yet. I'm capable of all levels of mistake.

OK, that's a good idea. Like I said, getting into these positions can be difficult. And I should have specified that I believe mating with two bishops is only possible if they opposite colored bishops (though I don't know why anyone would want to promote a pawn to a bishop instead of a queen.)

Upon further investigation, it is possible to get into the last position that I put up with two bishops and a king only (as far as I can tell) if black has another piece that can move besides its king and allows the light bishop to move on to the main diagonal and put the king into checkmate.

-mike

I've actually forced a mate with two knights, but the position was very special and this cannot be done under the vast majority of circumstances. If anyone's interested I could post the position.

Forced Mate: Mate cannot be stopped if played correctly

1 Rook
1 Queen
2 Bishops (can be somewhat tricky)
1 Knight & 1 Bishop (can be *very* tricky)


Stalemate: Mate cannot be forced despite quality of play on either side

1 Knight
1 Bishop

Special: Should be a stalemate but can turn into mate if player with King blunders badly.

2 Knights

In this case it was a bit different, as the player had a king and a pawn. This was used as leverage.

At some point, when I have one free, I could play it in a set-piece game.

2 Bishops (can be somewhat tricky)

Originally posted by Jacko007
genuis, alans username at the site can do the 2 bishops every time on me no prob.

a lot of practice needed though

David