Showing posts with label interference. Show all posts
Showing posts with label interference. Show all posts

15 March 2025

Tactics Training

These days, it seems that I spend more time doing puzzles online (chessdotcom mostly, but also Lichess and Chess Tempo) than working with positions in books. Still, for serious improvement in tactical vision and calculation, books are superior.

After racing through Thomas Engqvist, 300 Most Important Chess Positions (2018) in less than three months, I’m more highly motivated to keep 300 Most Important Tactical Chess Positions (2020) near the center of my chess activities through the rest of 2025. Four of the first five positions in the book have forcing continuations that run deep enough that I anticipate some challenge working through the book. Difficulty makes the enterprise worthwhile.

Today’s position arose in Mason,J.—Winawer,S., Vienna 1882. Engqvist’s analysis is instructive. At least three problems for players at different levels can be extracted from Mason’s combination.

Engqvist's position is before Mason's 40.Rxg5 (see photograph). If Black refuses the rook sacrifice, 40...Qf8 41.Rg6 controls the sixth rank. Then, 41...Rxf5

White to move
42.Qxf5! Qxf5 43.Rg7+ Nd7 44.Rxd7+ Kc8 45.Rxb8+ (only move) 45...Kxb8 46.Rb7+ and whichever way Black's king steps, Black's queen is coming off the board and White has a winning endgame.

After the line played in the game (40.Rxg5 hxg5 41.Qh7+ Nd7 42.Bxd7 Qg8--this position appeared as a exercise on chessgames.com in 2003--43.Rb7+ Kxb7), there is a more basic exercise position.

White to move
The discovery (44.Bc8+) is Engqvist's theme for this exercise, and the interference is an important aspect of why it works. Posters on chessgames.com and Engqvist valorize Mason's technique bringing home the full point for the resulting ending of queen and bishop vs. two rooks.

The Superiority of Books


For beginning students, the sequencing in such books as Sergey Ivashchenko, Manual of Chess Combinations (1997) and Susan Polgar, A World Champion’s Guide to Chess (2015) will lead to much more rapid growth in tactics skill than random positions online. Of course, with certain membership levels, chessdotcom and Chess Tempo allow training with particular themes and rating levels, so these can be tweaked with appropriate guidance.

For players who know basic patterns, but need work on strengthening calculation skills and assessing resulting positions after a combination, such books as Mark Dvoretsky, Secrets of Chess Tactics (1992), Paata Gaprindashvili, Imagination in Chess (2004), and Cyrus Lakdawala, Tactical Training (2021) offer abundant exercises.

Yakov Nieshtadt, Improve Your Chess Tactics (2012) is highly regarded for its organizational scheme and definitions, while Yuri Averbakh, Chess Tactics for Advanced Players (1992) articulates a notion of contacts that should be more common in chess literature.

22 May 2023

Misevaluation

After fortune shined on me in the earlier rounds, I was paired against Michael Cambareri on board one in the final round of the Inland Empire Open. We led the field with 3.5 each, followed by several players with 3.0.

I reached a comfortable position out of the opening and early middle game, but then failed to understand the demands of the position.

Stripes,James (1821) -- Cambareri,Michael (2005) [A80]
Inland Empire Open Spokane (5), 21.05.2023

White to move

18.Qf7?!

18.Qh6 now, would have been wise.
18.Qxg6 did not feel safe. Anticipating 18...Rg8, I missed 19.Rxf6 Rxg6 20.Rxg6 when White is better.

18...Qd6 19.Qg7

19.Bxg6 Rh8 20.h3 Kc7 21.Bf5 would have kept the advantage, but I was reluctant to snatch a pawn on the file where my king stood.

19...Kc7 20.Qh6 Rh8

White to move

21.Qf4

Planned and forced. Most of White's advantage has slipped away.

21...g5! 22.Qxd6+ Kxd6 23.Rae1

I believed that I was still better, but Michael's rooks were coming to life with threats that I feared more than necessary.

Black to move
23...Rh4!

Michael's defense against my intended e4 break picks up a tempo for doubling on the h-file.

24.g3 Rh6 25.e4

Long-planned and finally played. It is the best move, although I no longer believed so as the game developed over the next few moves. I had the sense that I had thrown away an advantage against Michael, as I have done in so many games.

Black to move

25...dxe4 26.Bxe4 Rah8

26...Nxe4 simplifies the ending in White's favor. 27.Rxe4

White to move

27.Bf5?

Thinking, wrongly, that I was clearly worse, I desperately sought counterplay in a series of harassing checks.

I rejected 27.Rf2! because I did not know how to meet 27...Ng4. Analysis with an engine shows that 28.Rf5! would have satisfied the demands of the position and left White with the better game.

Here also 28.Rfe2 would have been adequate against 28...Rxh2? (but Black has the better choice of 28...e6) 29.Bg2+-) 28...Rxh2 29.Rxg5 Nf6 30.Bg2+-.

27...Rxh2 28.Re6+

Although I was desperately trying to complicate a lost game, the engine says the position is equal.

28...Kd5

White to move

29.c4+??

A game losing blunder. Michael can take either pawn with a winning position. Michael expected 29.Rxe7 and his assessment that it was a better choice for me is correct. 29...Kxd4 30.Rxb7 Nd5 31.c3+ with equality.

29...Kxc4 30.Rxe7 Nd5?

A lucky break from my point of view.
30...Rh1+ 31.Kf2 R8h2+ 32.Ke1 Rxf1+ 33.Kxf1 Rxb2-+
30...Rxb2-/+

White to move

31.Rc1+ Kb3

31...Kxd4 walks into a little combination with a discovery and interference that picks up a rook. 32.Re4+ Kd3 33.Rh4+ Ke2 34.Rxh2++- 

32.Rxb7+ Ka2?

The rest is easy, except that my focus on winning the rook blinded me to checkmate.

32...Nb4 was the only defense that keeps the game very much alive for Black with difficult play for both sides.

White to move
Analysis after 32...Nb4

33.Rxc6 a5 34.Rc5 Rd2 35.Re7! would have been hard for me to find (35.Rd7 Rhh2=) 35...Rxd4 (35...Ka2! These engine lines are not clear to me at all.) 36.Rxa5.

Back to the position that did occur.

White to move

33.Bb1+ Ka1 34.Bh7+ 

I missed 34.Bd3+! Ka2 35.Bc4#, but the interference with the bishop was sufficient to provoke Michael's resignation.

1-0

Michael understood the game much better than I, but his errors came later and determined the final result. This game gave me first place in the event.

23 December 2016

Patterns and Calculation

There has been quite a bit of discussion concerning pattern recognition the past week on Chess.com. An article by a philosophy student,* "Pattern Recognition: Fact or Fiction?", provoked several dozen comments, many challenging the author's analysis. There is also a forum thread that spins off this article, "'Pattern Recognition' DEBUNKED", and another thread on the topic in a closed group for over the board players. The private group's thread started in August and inquires into the practicality of creating a pattern bank. Would it need 10,000 positions? More? I have contributed to all of these threads.

These discussions reveal an absence of a clear and accepted definition of patterns in chess. Are patterns a static arrangement of pieces that crop up with some regularity? Are patterns dynamic relationships, such as all pins constituting either single pattern or perhaps a specific category of patterns? What about typical pawn structures, such as the Caro-Kann structure that also commonly crops up in the Scandinavian Defense (see Panayotis Frendzas' review of Vassilios Kotronias, The Safest Scandinavian)?

These questions linger in the back of my mind, becoming active while reading a chess book, solving tactics problems, or playing. I am currently reading with an aim to reviewing Paul Powell, The Fighting Dragon: How to Defeat the Yugoslav Attack (2016). Powell makes pattern recognition central to his approach to opening study. My last youth lesson before the holidays focused on a simple checkmate combination that occurred in a blitz game and is part of my Knight Award tactics set (see "Pattern Training"). Next week at a chess camp, I am teaching a class on the Qh6+ sacrifice that ended this year's World Chess Championship match. Sam Copeland created a video on the topic for Chess.com. My work begins with his challenge to find more examples of this pattern.

This morning I solved two tactics problems on Chess.com's tactics trainer. The first one had a 2002 rating but took me a mere sixteen seconds. I had seen the same problem a few days ago and spent several minutes calculating before solving it successfully. When I saw it this morning, I recognized it after about ten seconds. Instantly, I knew that I had to attack the queen with my knight. A few seconds were needed to either remember or quickly recalculate the correct square among the two possibilities.

The second problem gave me more difficulty.

White to move

Naturally, I quickly looked at 1.Nxd1, rejecting it in the light of the fork of knight and pawn by 1...Rd4. It was clear that I needed to push my pawns, but experienced a good deal of confusion about how that was possible. Not only did it seem that the rook could stifle the ambitions of either pawn, but also I quickly saw that 2...Rxa8 or 2...Rxd8 would be checkmate. I spent some time calculating lines that begin with 1.Kg8 with the idea to support the d-pawn. These fail.

After about six minutes, I realized the rook was overworked and knew the first move.

Slowly a learned pattern emerged in my memory. Two connected passed pawns on the sixth rank are too much for a rook. But, my pawns are separated. Nonetheless, a solution dawned on me! 1.d7, pushing the pawn that the rook is not behind (as one would do if the pawns were connected). 1...Rd4 2.a7.

The rook cannot stop both pawns! But Black has another resource.

2...Bf3

White to move

Both promotion squares are guarded. Time to calculate further. Earlier, during my confusion, I had looked at Ng4+, seeing that it led nowhere. But, now, this move decoys the bishop from protection of the promotion square.

The decoy theme is certainly a dynamic pattern.

Of course, the king can move out of check, so the bishop will not be distracted so easily. In my calculation, I began to comprehend why the problem composer put a pawn on h4 (I'm assuming the problem is composed).

During my calculations, another pattern revealed itself: interference. 3.Ng4+ is the correct move! 3...Kh5 (3...Kg6 allows 4.Ne5+ forking king and bishop) 4.Nf6+ Kxh4 5.Nd5!

Black to move

If the bishop captures the knight, the rook no longer guards d8. If the rook captures the knight, the bishop no longer guards a8.

This problem could have been solved by pure calculation. That it took me more than ten minutes to solve, suggests that calculation was my best resource. Even so, along the way, patterns that were not instantly clear to me guided me and aided the calculation.

Because the problem took me so long, I gained only one point on my tactics rating. The average solving time is 2:34, but 2/3 of those who attempt the problem fail.


*He identifies himself as a teacher who was trained in philosophy. Readers of Plato understand that Socrates always thought of himself as a student, as a lover of wisdom who pursues knowledge and truth.

03 March 2015

Manual of Chess Combinations

In January, a young woman showed up at a youth chess tournament that I was running with an interesting book of chess combinations. She told me that this book had been recommended by her coach, who is a Russian master.* She also said that she was working her way through the book and finding many challenging problems that demanded creative and flexible thinking.

I looked up the book on Amazon and added it to my wish list. It is Sergey Ivashchenko, The Manual of Chess Combinations, vol. II (Russian Chess House, 2002).

I almost bought the book that day, but I waffled because I was also planning to buy the Encyclopedia of Chess Combinations, 5th edition (Chess Informant, 2014). At the 23rd Dave Collyer Memorial Chess Tournament, a used copy of Ivashchenko's was among the books that IM John Donaldson brought to sell. It was $10. I grabbed it instantly while he was still unboxing the other books.

Ivashchenko claims that this book is designed to lift players from 1600-1700 up to 2200 or higher. Hence, in theory, I should be able to work through the first two or three sections rather quickly, and then find more challenging problems. Indeed, I have solved a few of the early problems in two minutes or less. Nonetheless, a couple have proven more difficult.

After five minutes with Problem 15, I worked out the idea and verified that it would succeed, but I missed a nuance in Black's defense and so did not have the whole sequence correct.

White to move




*The young woman has been playing in my youth tournaments since fourth or fifth grade. She is now a high school senior. When she was in middle school, I coached her for a month or so to prepare her for the Idaho Girls State Championship, where she tied for first. She now plays as well as a solid A Class player, albeit with a much lower rating. I was happy that I was not paired against her in the Collyer. If she keeps playing chess through college, she will become a master.

01 March 2014

Tactical Success

When I play blitz or rapid chess, I miss a lot. Even slower time controls do not prevent missing things. However, under time pressure, tactical mistakes are the norm. In the positions below, however, I found the correct move.* All come from one day's rapid play online.

Black to move

White to move

Black to move

I was hopelessly lost in the next game, but my opponent made a few errors to give me this nice position.

White to move

Black to move



*"Correct" is defined as playing the move that Stockfish prefers.

28 October 2013

Interference

Playing the White side of a French Advance, I find myself looking through some master games. These are neither won nor lost in the opening. In Vorobiov -- Volkov, Moscow 2004 White prevailed in the endgame.

White to move

White gave up a rook to assure that his pawn would promote.

57.Re4! Rd3+ 58.Kg4 dxe4 59.e7

Even then, however, Black had a pawn that threatened to complete its journey.

59...Kd2 60.e8Q e3 61.Kf3 Rxb3 62.Qd8+ Ke1 63.Qd5 Ra3 64.Qc5 1-0

Black to move

This fork of rook and pawn ends things. After White's queen is exchanged for rook and e-pawn, White's h-pawn will promote.