Monday, February 18, 2008

Deceptive Tactic

It took me a few minutes to solve this tactic from "Chess Tactics for Beginners":

The reason is that this looks like it's set up to be the old "windmill" or "see-saw" tactic: rook moves along a rank or file to deliver a discovered check; king moves; rook returns to original square to check. This is normally combined with other threats, such as merely gobbling material with the rook. I was thinking, "well, this is a tactics problem, the answer must involve this tactic" and kept trying to make it work.

Here, rook moves along the 7th rank or the g-file don't accomplish anything. I briefly wondered if the trick was to set up a winning zugzwang after moving the rook, but (for example) 1.Ra7+ Kg8 2.Bg7 can be met by 2...Rf7=.

Then I realized that a safe king move would also put black in zugzwang. Correct is 1.Ka2! Only the black rook can move, and it will be lost to the discovered check (e.g. 1...Ra8+ 2.Ra7+).

However, 1.Kb1 doesn't work, because here the white rook can't block the check after 1...Rf1+, e.g. 2.Ka2 Rf8.

The hardest part of this problem was letting go of my preconception of what the solution must involve, and postponing the "obvious" windmill pattern for one move. Sometimes familiarity with standard tactical motifs can blind you to other tactical possibilities.


transformation said...

always a great pleasure to see your work :)

tanc(happyhippo) said...

i have to admit, it took me quite a long while to think before I got it. i was stumped. but then i thot.... hmmm... if only it was Black to move.... then the answer quickly came to me.

very tricky tactic indeed. nice puzzle.

Wahrheit said...

Thanks for sharing that one, I went down the same false trails as you for awhile, it's always good to be reminded that the right move may be subtle and hidden.

Blue Devil Knight said...

That is a gem that I remember well. I love the quiet tactics.