Q and B Mate?

Can a Queen and a Bishop force mate without the help of the King?

I think so...I mean logically I can see the checkmate but it might take awhile to force it

Originally posted by AThousandYoung
Can a Queen and a Bishop force mate without the help of the King?

Originally posted by AThousandYoung
Can a Queen and a Bishop force mate without the help of the King?

Originally posted by SwissGambit
Trick question!

It cannot be mate without 2 Kings on the board. Without 2 Kings on the board, it is no longer Chess, but some bizarre variant game masquerading as chess.

Agree with Yuga. Against a bare king, sure it can. I'm not sure what the most efficient method is, although I see engines do it all the time, and it never seems to take more than a handful of moves.

But if you're not worried about efficiency, it's a trivial problem. Just the queen alone can force the king to the last two squares in one of the corners. Then, once the king goes to the corner square, you check it with the bishop and finally deliver mate with the queen on the next move.

Edit - I forgot to say that this works if the bare king goes to a corner of the same color of the bishop. If he goes to the other corner, then the last bishop move isn't a check, but you get the idea.

Mad Rook is right.

One method is to use the Queen giving the opposing King 'knight checks'
ie. pretend the Queen is a Knight and check the King.

You can then force the King onto the back rank.

**************BEWARE****************

Although the Queen cannot deliver mate by herself
she is very capable of giving stalemate.

Avoid this positon with Black to play. It's Stalemate.

Originally posted by AThousandYoung
Can a Queen and a Bishop force mate without the help of the King?

Originally posted by AThousandYoung
I didn't say the Kings weren't on the board. I just said the winner's King doesn't help force the mate.

Originally posted by SwissGambit
Ahh, very good. You got me.

[fen]8/8/8/8/3k4/8/B7/KQ6 w - - 0 1[/fen]

Just for kicks, I tried it against Fritz 9 from this position. Play went
1. Qc1 Ke5 2. Qc4 Kf5 3. Qe6+ Kf4 4. Bd5 Kg5 5. Qf7 Kg4 6. Qf6 Kg3 7. Qf5 Kh4 8. Qg6 Kh3 9. Bf3 Kh2 10. Qg2#

Pretty trivial to win this; the only real danger is stalemate.