Tuesday, June 24, 2008

Preview of Forcing Chess Moves

{edit: fixed the first diagram}
{second edit: fixed the third. Good grief!}

I've been slowly working my way through Forcing Chess Moves by Charles Hertan. I see that it was reviewed at the Chess Cafe here, so I'll just add a few impressions so far.

First, be forewarned: the author uses ALL CAP EMPHASIS for certain KEY SAYINGS that are repeated throughout the book. I understand the pedagogical intent, but it's distracting. I still haven't decided yet if it's a net plus...if at some point I play a game and suddenly my COMPUTER EYES kick in to realize it's time for BRUTE-FORCE CALCULATION to find the winning move, then I suppose it will be proven effective.

The theme of the book is to train you to analyze the most forcing candidate moves first. What makes this book unique is that it's overall goal appears to be to expand your perception of what a forcing move is. The premise is that a computer will find winning moves that often are omitted as candidate moves by humans, because at first glance they look bad. The author hopes to train the reader's COMPUTER EYES so that they will consider these odd, but forcing moves, as candidates in their own games.

I'm still in the earlier part of the book, which more closely resembles a standard collection of advanced tactical problems in that the forcing moves tend to be checks and direct sacrifices. An example:

simul 1995

1... Qh2+!!

"...it is the most FORCING MOVE on the board. Perhaps your COMPUTER EYES are even able to follow the chain of forcing moves and find the tricky but logical 'quiet forcing move' on move 4?"--Hertan.

2. Kxh2 Rxf2+ 3. Kh1 Ng3+ 4. Kg1 Ree2 0-1

A standard tactical problem, although the not-most-forcing (i.e. non-check) 4...Ree2 could be considered foreshadowing of what's to come.

Here is an example featuring a much less obvious forcing move:

Kavala 2004

1. Qb6! a6 (1... axb6?? 2. Nxb6#; 1... Nd7 2. Qxa7) 2. Nc5 Ne8 (2... Nb5 3. Bxb5
axb5 4. Nxb5 cxb5 5. Nxb7+) 3. N3a4 Nd6 (3... Qc7 4. Qa7! Rd7 5. Nb6+) 4. Qa5 1-0.

I found that the author's comments can be misleading, and that it's better to try and solve the problems yourself with an open mind, and then consult the book text. For example, for the following problem the author says: "Here a beautiful stock mate on h7 relies on a SELF-BLOCKING ENEMY PAWN on g5 containing the black king. Excellent COMPUTER EYES are in play, as all five white moves are the MOST FORCING:"

Bad Pyrmont 1933

1. Qd8+ Kg7 2. Rxg5+! hxg5 3. h6+!

I missed this move. I saw that 3. Qxg5 was with check, and assumed this must be the most forcing move...what's stronger than a queen check?... but saw that 3... Kf8 4. Qd8+ Kg7 5. Qg5+ draws. Further, Fritz found that Black could win with 3...Kh8.

3... Kxh6 4. Qh8+ Rh7 5. Qxh7#.

One thing I've found in analyzing my own games is that Fritz will find moves that are clearly strong, but I would never have considered the first move of the sequence. Sometimes, the tactic will defy categorization as a fork, pin, skewer, deflection, removal of the guard, etc, but simply be a move that works. My impression is that Hertan's book may help open the reader's eyes to these opportunities. I also think that endgame training can also help, because sometimes the winning move can only be found by BRUTE-FORCE calculation. More on that in a future post.

I feel that the standard practice of studying tactical motifs can blind us to other possibilities if we can't classify them as one of these motifs. This is not to say that studying basic tactics is detrimental. My point is that if humans can't name or categorize something, they have a hard time recognizing it. For example, some languages have words that cannot be adequately translated into others, and describe concepts or feelings particular to that culture. I wish I could come up with a good example of that on short notice, but "schadenfreude" comes close...in recent years it's crept into common English because it fills a gap in our language. Similarly, let's say a certain winning move puts the opponent into zugzwang, forcing a self-blocking move that allows a successful king-hunt and mate. For us, that may be an example of BRUTE-FORCE CALCULATION of QUIET FORCING MOVES. For some alien chess culture, that may be a classic example of a "glibberfunken" motif that every alien schoolboy knows.