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:

NN-Keene
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:

Gershon-Mihailidis
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:"


Weissgerber-Rellstab
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.

Tuesday, May 27, 2008

Another Example of Engame Transitions

This post is in part to let people know I'm alive, and in part to whet my blogging appetite. The end of the semester has been a busy one. I have a couple of book reviews that I've been dragging my heels on but should post shortly.

This is from an online blitz game (2+12 time control). Evaluate 1.Rb5.



I was Black and had been suffering all game. Finally my opponent slipped with 1.Rb5?? I had been hoping for this, but didn't think my opponent, who had played credibly to this point, would fall for it. Even if my opponent had been in time trouble (which he wasn't), 12 seconds is enough time for someone our level to follow the most forcing line and see that this move is bad.

1...Rxb5! is forced, otherwise the h-pawn drops and the connected passed pawns win. After 2.axb5, black steps into the square of the passed pawn, e.g. 2...Ke7:



Now Black will have a protected passed pawn, which takes care of itself while Black's king gobbles the isolated passed b-pawns: 3.Kg5 g6! 4.f4 Kd6 5.f5 Kc5 6.fxg6 fxg6 0-1.

It was only necessary to follow the most forcing moves 4 ply ahead (up to 2...Ke7) to see that White's chosen move loses--assuming a basic knowledge of pawn endgames. Knowing the rule of the square means, for example, that you don't have to calculate ahead another 6 ply to see whether White can promote a pawn safely. It also means you don't need to calculate much to convince yourself that Black's kingside pawns will be safe. After g7-g6, Black has a protected passed pawn. If White tries to capture the base of the pawn chain, the king will be out of the square of the leading pawn, which will go on to queen. If anything in this last paragraph isn't clear to you ("What's 'the square'?") I strongly recommend picking up a basic endgame book (Silman, Pandolfini, or Alburt for example) and getting started.

One possible explanation for my opponent's move is just a silly oversight (I know those all to well), perhaps thinking Black's king wouldn't be able to get into the square of the pawn. It's also possible that they just haven't studied endgames much, and that certain themes such as the square of the pawn or the strength of a protected passer were not yet second-nature. My reason for choosing this position was to demonstrate once again the importance of endgame study: it's not just so that you know the technique required to win a certain endgame, but also so that you can spot transitions to winning endgames...or, to avoid transitions to losing endgames.

By the way, the theme of analyzing the most forcing sequence of moves is foreshadowing for my next mini-book review.

Saturday, April 19, 2008

Brief Update: Preparing for Summer

I've had a couple posts in varying stages of completion for a while now, but between real-life distractions and the amount of work they've turned into, I've delayed posting them for a while.

I hope to post a review of Chess Endgame Training by Bernd Rosen soon (short version: me likey!) and some endgame analysis in about a week. I just wanted to confirm that I'm still alive, and also give myself a little kick in the pants to produce something worth reading soon.

I'm looking forward to summer evenings on the porch with a book and a chessboard, and putting a dent in my list of master games to play through.

Tuesday, April 1, 2008

Important Addition to Marin's A Spanish Repertoire for Black

I think that Marin's two-volume opening repertoire based on 1.e4 e5 (Beating the Open Games and A Spanish Repertoire for Black) is amazing, and packed full of chess knowledge. However, the two books are targeted towards either more-advanced players (particularly the latter), or the ambitious student. They're also directed towards main-line players rather than offbeat-variation players. This means that the reader has to plug a lot of holes themselves, as they find that the opponents they encounter at their level frequently play a line not covered.

I just checked qualitychessbooks.com, and found that a 25-page addendum to ASRFB is available for download in .pdf format. It covers, among other gaps, my biggest problem with that book: no discussion of the departure from the Chigorin mainline with 12.d5 (instead of 12.Nbd2). I see the former more than the latter in my online games, and it's the #2 line by statistics (74 out of 1051 Grandmaster games, according to my home-made opening book; 478 out of 6050 games total).

In other news, it appears that the first volume (BTOG) is about to be reissued as a second edition. When I bought it, it contained a 4-page insert covering two omitted lines. It sounds like a combination of popular demand and reader critique has prompted an upgrade. According to the publisher, it should be out very soon (Spring 2008).

It's annoying when you just buy a book and a new edition comes out shortly after. When the second edition of Dvoretsky's Endgame Manual came out, I decided that I didn't need to worry about the second edition until I completed the first (which is still a loooooong way off). Also, I've heard the quality of print for the second edition of Dvoretsky wasn't as good. However, Marin's BTOG has become indispensable for me, so I'm looking forward to seeing what's been added in the second edition.

Real chess players will roll their eyes because I've held Dvoretsky on the back burner while salivating over an upgrade to an opening book. Well, like the banner says: Do as I Say, Not as I Do.

Friday, March 21, 2008

Polgar Error

I was going over some of the basic endgames from L. Polgar's Chess: 5334 Problems, Combinations, and Games. The book's analysis for Position #5113 is incorrect: Black surprisingly can draw!

White To Play


The provided solution is 1.e8=Q, followed by 1...e1=Q(?) 2.Kf6+ and White wins.

However, Black has a surprising draw if instead they play 1...Ke3!:


At this point, I'd like to quote from Muller and Lamprecht's Fundamental Chess Endings: "If {a single pawn} has advanced to the seventh rank and is threatening to promote, everything depends on whether the attacking king can assist the queen. With a central pawn, this is almost always possible, no matter how far away the king is." I briefly touched on these endgames in this earlier post.

Here we have an exception to this "almost always" rule. It turns out that White has an unfortunate placement of king and queen. For example, 2.Kf5+ Kf2!



Black's king hides in the shadow of White's, and supports the pawn's promotion. The queen lacks any move that prevents Black from obtaining their own queen (e.g. by delivering check or by pinning the pawn to the king).

I've been entering endgame positions for books into databases. One reason is that I can later play these positions vs. the computer and practice my endgame technique. Another reason is that I can explore variations not mentioned in the books to make sure I understand the positions thoroughly. However, here we can see one final benefit, especially if you have endgame tablebases at your disposal: you can find errors in old analysis and learn new tricks.

Friday, March 7, 2008

Help Finding Pocket Set Replacement

I bought this pocket set off of the USCF web site sometime around 1995:



I still have all the pieces, which for me is some sort of miracle. However the plastic case is cracking and I'm not sure how much longer it will last.

I'm calling out to the community for help in either identifying a supplier for this pocket set, or the nearest equivalent. Here is what I find special about this set:

  • The board is metal, not vinyl.
  • The board does not fold.
  • The board can be held comfortably in one hand.
  • The magnets are very strong. There's no chance at all of the position being lost in transit.
  • A plastic lid snaps on with magnets, protecting the pieces in transit.
  • The set is thin... roughly 5 mm. Almost thin enough to act as a bookmark:


The only negative thing I can think of is that there is limited room to place pieces not in play. If I'm in the middle of a game and want to save it, I have to creatively place the pieces so that they avoid the spots where the lid's magnets touch the board.

My backup set is a metal case set I grabbed at Starbucks. However, the board is hinged, so there's a barrier wall that runs between the 4th and 5th ranks. The files also don't quite match up where the hinge is, and I find the slight offset a bit distracting. Finally, the magnets aren't as strong as I'd like.

This is your mission, dear readers. Can anyone tell me who the maker of my set was, and if it can still be found? Or, does anyone know of a pocket set that would be a worthy replacement?

Fly, my monkeys! Fly!

Thursday, March 6, 2008

Adgj

Adgj

Edit: Wow, three responses!

I was trying to use the new remote blogging tool for Blogger, and thought I had failed at a test message from my new phone. Didn't check to verify the fail though.

The pictures that I tried to send from my phone will be in my followup post.