Sunday, October 4, 2009

Mate in Two

The following Mate in Two problem is from Yusupov's Build Up Your Chess I, and I think it's the hardest mate in two problem I've come across so far.

I'm not going to give away the answer, but it's a good test of your ability to analyze a dense thicket of short variations.

Laszlo Polgar's Chess: 5334 Problems, Combinations, and Games has a ton of mate-in-two problems in it, and I occasionally turn to a random page and try to solve some. Some of them are really devilish, and are good practice for practicing Kotov-like analysis (trying to analyze each branch of a variation once and only once).

I'm going to try and get a couple more chapters of Yusupov's book knocked out this afternoon.


Hank said...

That's a great puzzle! It took me a few minutes to realize that "forcing moves" like checks where not going to help, but in fact what was required was to place Black in the "ultimate zugzwang" situation! After realizing that Black's a6 pawn was the only piece that could *clearly* waste a tempo for Black without potentially allowing any new mating possibilities for White, I came up with the candidate move 1.Qa5 (blockading that pawn).

This leaves Black with no pawn moves (or king moves), so one of Black's bishops or rooks must move. I saw right away that any bishop move that block's his rook's coverage of d5 or e5 would allow a queen mate on the square that is no longer guarded.

It was big trickier to see that any rook move to the 6th or 7th rank would similarly block a bishop's coverage of either f5 (allowing a knight mate on f5) or b4 (allowing Qxb4#).

So this left 4 more possible replies by Black that I had to account for, which I verified as follows:
1...Rd5 is met by Qxd5#
1...Re5 is met by Qxe5#
1...Bf5 is met by Nxf5#
And the one that took me a little longer to see is that
1...Bc5 can be met be Qa1#!

Wow - talk about a thicket of variations!

Thanks for sharing this extremely cleverly conceived puzzle!

Best regards,

Grandpatzer said...

Yes, what made it tricky was that White's first move isn't a check or capture, and also Black's large number of legal moves--but all resulting in a mate-in-one position.

Anonymous said...

And 1...Be6 is 2.Qe5 mate.

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Rodrigo Montes said...

I done less than 3 minutes...

Ed said...

But Nc2 is mate in one. Why is that not the real answer?

John said...

It is very easy 1.Qa5!! and zugzwang!