Sunday, September 28, 2008

Cecil's Saturday Puzzle - September 27, 2008

White to move and mate in 3 (Jacobs)

A most unusual position.
I immediately saw a mate in 5 with

1.Qd1 axb1(Q) 2.Nc2+ Ka2 3.Nb4+ Ka1 4.Qa4+

1. Nc2+ Kxb1 2. Na3+ Ka1 obviously doesn't work.

I tried a line (which I forgot now except that the Q was mating on e4 except for the pawn on d5.
So, let's try something nonintuitive (like some of the other problems we have looked at). With the idea of Q having access to the h7-b2 diagonal.
1. Qe8
one line ...axb1(Q) 2. Nb3+ Ka2 3.Qa4#

1.Qe8 Kxc1 2. Qb3+ Ka1 3. Nb3#

so the bishop must move 1. Qe8 Bc3 2. Nb3+ Kxb1 3. Qg6#

Is that it ?

Two questions to answer. What is the difference between Qe8 and Qd7 ?
Both give access to the same diagonal even after e6. And what if Black plays the bishop to b4 and block a mate by Ba3. Because otherwise the bishop is rather useless as all the mating lines involve white squares. But that doesn't appear to be a factor.

Speaking of blocking...what if instead of axb1(Q), Black tries axb1(N) to block on a3 - I think that ruins all my efforts.

But 1. Qd7 axb1(N) 2. Nxc2+ Ka2 3. Qxd5# works !
and the other lines work with the Q going to f5 or h7 instead of g6.


Anonymous said...

Isn't Ng6+ and Qd5+ forced mate?

Anonymous said...

isn't Ng6+ and Qd5+ forced mate?

Chess Manitoba said...

Well, it would be if the board was reversed !

But by convention - White is at the bottom of the board (and the coordinates on the edge of the board also indicate this)

Anonymous said...

Do you allow all your players to have any computers/laptops/blackberries/cell phones or any sort of equipment be at large during tournaments? As you know, with the technology now, players can just have all these gadgets to win purposely.

You should restrict them to have a fair game at any time for all players.

Chess Manitoba said...

No assistance of any type is allowed.