22 January 2018

Checkmate Data

It is commonplace to speak and write about checkmate patterns. Certain recurring checkmates happen over and over again in games no matter the skill level of the players. Of course, once players rise above a certain level, checkmates become rare due to resignation either due to a checkmate threat or one player gaining an overwhelming material advantage.

Do claims about checkmate patterns stand up to data from played games? It is a simple, albeit time consuming matter to examine every game in the database that ended in checkmate. It may be possible to name every pattern in these checkmates and then list them in order of frequency.

Running on my desktop, ChessBase was able to find every game in my largest database ending in checkmate in about one minute. As I prefer quality over quantity, my largest database is smaller than many others, containing a mere 5.9 million games.

In this database, 148,127 games end in checkmate.

The last piece to move was most often the queen, and presumably this piece was always giving the check that is checkmate in all of them. Queen moves account for 59% (87,894) of the games in this selection.

The rook is the last piece to move in 24% (35,473) of the games. Most often, the rook is likely giving check and mate. However, a rook move can produce a discovered check by bishop or queen.

A little more than 7% (10,990) of the games ending in checkmate involve a knight making the last move of the game. Some of these, no doubt will be discoveries, but it's a reasonable prediction that the knight is checking the enemy king in most of them.

A bishop moves to checkmate the opponent in 6% (8,898) of the games.

Pawn moves account for slightly more than 3% (4,847) of the games. It will be interesting to study how often the pawn itself delivers the decisive check.

King moves account for a mere 25 games. More than half of these are by castling, so a rook is giving checkmate. The king cannot deliver check, but it can cut off the escape of an enemy king.

For example, in this game between two youth players from 2005, White's king moved so as to check by the rook and cover one of the escape squares.

White to move

One of the games that ended with O-O# could have gone on two moves longer with better defense. The combination strikes me as instructive. It is from Suess -- Hurme 1969, a game played as part of team world championship qualifier.

White to move

16 January 2018


Black to move

From a blitz game.

13 January 2018

Beware the Horse

Where should the queen move?

White to move

This position caught my interest. It appears in "The Art of Unequal Exchange" by Ivan Ivanisevic in Chess Informant 134, which I received last week. This article is quite interesting and offers study material that promises to improve my game, as well as helping me develop some materials for teaching young players.

25 December 2017

Holiday Cheer

I usually play a game or two of online blitz on holidays. These days are devoted to family time, but there are always a few moments when everyone else is sleeping or otherwise occupied, so I sneak in a game of chess. This morning, the investment of a knight gave me a nice position in a classical French.

White to move

My bishop is prepared to come to d7 with tempo, then the other rook can join the fray and all of my pieces will be aiming at White's royal family while his pawn storm is less threatening than the skiff of snow that fell on my deck overnight.


20.Qa3 seemed necessary.

20...Bd7 21.Qa3 Rfb8

My opponent realized the hopelessness of his position and wished me Happy Holidays!

23 December 2017


Several of my students have seen this position this past week. None have succeeded. It is one that I use from Dvoretsky's Endgame Manual.

White to move

25 November 2017


For the past three months, I have been too busy with other matters to create articles for Chess Skills. I have studied no chess. My chess activities have been limited to coaching and a few games of online blitz most days. Things should get back to normal in December.

I had White and the move from this position against a FIDE Master on Thanksgiving morning. It was my third victory against a titled player in one week. The position will be useful for my elementary students.

White to move

02 September 2017

Thompson -- Morphy, New York 1857

Paul Morphy's first opponent at the First American Chess Congress was James Thompson. He had been born in England and emigrated to the United States as a child. After completing his education, he established himself in business in New York City, where he came to be known as a formidable chess player. In 1853, Thompson won the first tournament among members of the New York Chess Club. He represented New York in several correspondence matches with other cities.*

Morphy beat Thompson 3-0. The games offer useful lessons concerning opening principles, as Morphy easily gained better mobility and coordination of his pieces. Two of the games featured endgames where Morphy demonstrated how to convert a small advantage. In the third game, which I present here, a tactical error in the middlegame cost White a pawn. In the endgame Morphy's bishop proved far stronger than Thompson's knight. Having an extra pawn made the game easier.

Morphy won this game in the middlegame, but had to demonstrate proper endgame technique to complete the victory.

Thompson,James -- Morphy,Paul [C54]
USA–01.Kongress New York (1.3), 08.10.1857

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.c3 Nf6 5.d3

This move is superior to 5.d4. I tend to play the inferior move (see "Materialism").

5...d6 6.h3

I have my doubts about the merits of this move (see "Wasting Time" for Phillip Sergeant's criticism and Macon Shibut's rejoinder regarding the frequency that Morphy's opponents played this move).


6...a6 seems the top choice today. With Morphy's move, White has a problem: How should he resolve the tension between the bishops along the diagonal leading to f7?

White to move


I might prefer 7.Bxe6 fxe6. Black's control of the central squares with his pawns more than compensates for any apparent weakness on the kingside. However, White's prospects might be better than in the game. The combination of the unnecessary prophylactic 6.h3 and this retreat of the bishop puts White two tempi behind. Soon, Black seizes the initiative.

Here we have a position that is typical of Morphy's games against all but his strongest opponents, and even a few games against his strongest. A few moves into the game, Morphy has all of his minor pieces mobilized. Many of his opponents, on the other hand, have fallen behind.


Morphy seizes the opportunity to take the initiative.

8.exd5 Bxd5 9.0–0 0–0 10.Bg5

Black to move

Thompson is ever alert to tactical possibilities. He threatens to force a weakening of the pawns in front of Black's king.

10...Bxb3 11.axb3 h6 12.Bh4 g5 13.Bg3 e4

Thompson's tactical threats have forced Morphy to play this move. However, Black's position is superior due to White's difficulty bringing the b1 knight into the game. This positional weakness will prove decisive.

White to move

14.Ne5 Nxe5 15.Bxe5 exd3 16.Bxf6

16.Nd2 might be better than exchanging the only active piece in order to immediately regain the pawn.

16...Qxf6 17.Qxd3

Black to move

Now, Morphy mobilizes his rooks with further gain of tempi. Meanwhile, White's queenside knight and rook remain spectators to the action.

17...Rad8 18.Qc2 Rfe8 19.b4 Bb6 20.Na3

20.Nd2 is now impossible in the light of 20...Re2.


Morphy prevents Nc4, and also prepares a battery along the diagonal leading to h2.

21.Rad1 c6 22.Rd3?

White's position was slightly worse. Now, it is lost. However, Black must strike vigorously, or White's will equalize.

Black to move

Surprisingly few chess players have found the correct plan for Black when I have posted this position online.

22...Bxf2+ 23.Kh1

23.Rxf2 loses instantly. 23...Re1 24.Rf1 Rxf1#.

23.Qxf2 loses the exchange. 23...Qxf2+ 24.Rxf2 Re1+ 25.Kh2 Rxd3

23...Rxd3 24.Qxd3 Re3

White to move

Black's checkmate threat is quite serious.

25.Qd8+ Kg7 26.Qd4+

26.Qd7 Bg3!

26...Qxd4 27.cxd4 Re2 28.Nc4 Re1 29.Rxe1 Bxe1

White to move

White managed to fend off the checkmate threats and enter a minor piece ending down a mere pawn. However, Black's bishop will prove vastly superior to White's knight.

30.Na5 Bxb4 31.Nxb7

This moment in the game can be useful for provoking a discussion of schematic thinking.

31...Kf6 32.Nd8 c5 33.Nc6 Ke6 34.dxc5 Bxc5 35.g4

It is hard to criticize White's effort to hinder Black's pawn majority on the kingside in this manner, but the problems on the queenside prove fatal. The knight is helpless to manage workloads on both sides of the board and the king alone cannot battle Black's forces.

Black to move

35...Kd5 36.Nd8 f6

Reducing a vulnerability that could permit White back into the game.

37.Kg2 a5 38.Kf3 a4 39.Ke2 Bd4

Only now does Morphy attack the unprotected pawn after preventing its advance.

White to move

40.Kd3 Bxb2 41.Nf7 Be5 42.Kc2 Kc4 43.Nd8 a3 44.Nb7 a2 45.Na5+ Kb4 46.Nb3 Ka3 0–1

The final position offers a nice illustration of zugzwang.

*The biographical sketch of Thompson in Charles A. Gilberg, The Fifth American Chess Congress (1881), 77-80 provides these details. The Congress was held in 1880. The book contains a detailed history of the first four congresses, as well as the games of the fifth.

11 August 2017

Critical Moments

How do you analyze a chess game?

I do several things, but the first step--whether my own game or one played by others--is identifying the critical moments in the game. When did the loser reach a technically lost position?

Today was the last day of my tenth annual youth chess camp. The students spent the week--fifteen hours--solving exercises in a workbook (available on Amazon), playing tournament games, discussing games and parts of games with me and with each other. Throughout the week, I stressed a learning process that extends well beyond the week of camp: work on endgames, then tactics and planning, then openings, then study whole games. When they arrived this morning, I had two positions on the two demo boards. We talked about the endgame first. Then we talked about the middlegame.

Black to move

With two legal moves, Black chose the one that loses.

White to move

White turned an advantage into a lost game by moving the queen to the wrong square.

The whole game with annotations at the critical moments is offered below.

Stripes,J. (1911) -- Internet Opponent (1892) [A43]
Chess.com, 10.08.2017

1.d4 e6 2.c4 c5 3.Nf3 cxd4 4.Nxd4 a6 5.g3 Qc7 6.Qc2 b6 7.Bg2 Bb7 8.e4 Nc6 9.Be3 Nxd4 10.Bxd4 Nf6 11.0–0 Bc5 12.Bxc5 bxc5 13.Nc3 h5 14.Rad1 h4 15.Qe2 hxg3 16.fxg3 Ke7 17.e5 Nh5 18.Ne4 Bxe4 19.Qxe4 Rag8 20.Rd6 f5 21.Qh4+ [21.Qd3] 21...g5 22.Qh3 Nf4 23.Qxh8 Ne2+ 24.Kf2 Rxh8 25.Kxe2 Rxh2 26.Kf2 g4 27.Rfd1 a5 28.Kg1 Rh8 29.b3 Rd8 30.Bc6 dxc6 31.Rxd8 Qxd8 32.Rxd8 Kxd8 33.Kf2 [33.a4 Ke7 34.Kf2 Kf7 35.Ke2 Kg6 36.Kd3 Kg5 37.Ke3 f4+ 38.gxf4+ Kf5 39.Kf2] 33...Kc7 34.Ke3 Kb6 35.Kf4 a4 36.Ke3 Ka5 37.bxa4 Kxa4 38.Kf4 Ka3 39.Kg5 Kb4 40.Kf6 Kxc4 [40...f4 41.gxf4 g3] 41.Kxe6 Kd4 42.Kxf5 c4 43.e6 c3 44.e7 c2 45.e8Q c1Q 46.Qd7+ [46.Qe4+ Kc5] 46...Ke3 47.Qe6+ Kf3 48.Qe4+ Kxg3 [48...Kf2 49.Qf4+ Qxf4+ 50.Kxf4 c5] 49.Qxg4+ Kf2 50.Qf4+ Qxf4+ 51.Kxf4 Ke2 52.Ke4 Kd2 53.a4 Kc3 54.a5 Kb4 55.a6 c5 56.a7 c4 57.a8Q c3 58.Kd3 c2 59.Kxc2 1–0

After these two positions, we looked at Fischer -- Stein 1967, which they have in their book. Following that presentation, the students worked in groups studying other great games. Then, they played the last round of their tournament. During the last fifteen minutes, we went through the whole game from which I had extracted the two positions that we began with nearly three hours earlier.