15 July 2017

Checkmate Patterns

Some readers of Chess Skills may have been disappointed that my postings have been limited the past two months. Much of my chess time has been devoted to preparing lessons for my camp in August. A standard feature of my annual summer chess camp has a been a camp workbook that each student receives. This year's workbook will be more than twice the size of my previous largest, which ran 92 pages. This year's workbook will be available through Amazon. My title has changed three times in the past two days. Currently, my working title is Five Days to Better Chess: Essential Tools.

In this summer's camp, each day will be focused on one topic. Each topic will be layered to accommodate students of a wide range of skill levels. There will be group activities and individual activities. The topics in sequence are checkmates, endings, middlegames, openings, and great games.

On the first day, beginning students will learn three basic checkmates against a lone king: queen and king, rook and king, and queen and rook. Then, they will move on to where the second tier group begins. Here is a sample from my workbook in progress.

Checkmate Patterns

It is not clear precisely how many ways exist to deliver checkmate. Nonetheless, my study of many thousands of checkmates in my games and in the games of others has convinced me that there are only a few dozen basic checkmate patterns. Most opportunities to force checkmate will fall into a much smaller set, perhaps two dozen. My research is not original, but merely confirms what many chess masters have found through the ages.

My booklet, “A Checklist of Checkmates”, lists 37 patterns. Portions of this booklet have been distributed to my students for the past fourteen years. The booklet contains illustrations of patterns from games, followed by exercises.

Several books have helped me learn and teach these patterns. The best one in my view is The Art of the Checkmate (1953) by Georges Renaud and Victor Kahn. When I wrote “A Checklist of Checkmates”, the English translation of The Art of the Checkmate was available only in descriptive notation, which few children learn these days. Since then, it has been republished in algebraic. After The Art of the Checkmate, the most useful book that I have found is Mikhail Tal, and Victor Khenkin, Tal’s Winning Chess Combinations (1979)—this book is new to me, having purchased it a few months ago.

Tal and Khenkin arrange their book with one chapter for each piece, followed by combinations of pieces: rook, bishop, knight, queen, pawn, two rooks, queen and bishop, and so on. Each chapter presents a small number of essential patterns. This arrangement is similar to the arrangement that I created for “A Checklist of Checkmates”, reproduced here.

The Checklist

Corridors
1.Back-rank mate
2. Edge-file mate
3. Two rooks (or rook and queen)
4. Two pigs
5. Anastasia’s mate
6. Max Lange’s mate

Diagonals
7. Fool’s mate
8. Boden’s mate
9. Parallel diagonals
10. Reti’s mate

Intersections
11.Rook and bishop
12. Opera mate
13. Pillsbury’s mate
14. Morphy’s mate
15. Two rooks and bishop

Knights
16. Smother mate
17. Smother mate with pin
18. Two knights
19. Corner mate
20. Arabian mate
21. Modified Arabian mate
22. Knight and bishop mate

Queens
23. Edge checkmate
24. Swallowtail
25. Dovetail
26. Epaulette
27. Half-epaulette
28. Queen and bishop
29. Queen and knight
30. Queen and rook

Combinations
31. Legall’s mate
32. Lolli’s mate
33. Mayet’s mate
34. Anderssen’s mate
35. Blackburne’s mate
36. Damiano’s mate
37. Greco’s mate

Just as there is no certain definite number of possible patterns, there is considerable variety in the naming of patterns. For example, my “two pigs” checkmate has been called “blind swine checkmate” in other books, including Vladimir Vukovic, The Art of Attack in Chess (1965). I dislike the name blind swine because that term’s origin comes from a grandmaster discussing a situation when two rooks could force a draw, but not force checkmate—hence, they are blind. I see blind swine as a drawing combination, not a checkmate pattern. Rooks on the seventh rank are sometimes called pigs, or swine.

Although there is not universal agreement on the number and names of common checkmate patterns, many of these names are in common use. An entry on Wikipedia lists many of them. Some names, such as Reti’s mate and Anastasia’s mate, have very specific histories. On the other hand, one name, Pillsbury’s mate, comes from a specific game that was not played by Pillsbury. Renaud and Kahn present the game as one of his, although it was played by others. There are several important ideas in chess that are misnamed from a historical point of view. For example, the Lucena position (part of the second day lessons) does not appear in Luis Ramírez de Lucena, Repetición de Amores e Arte de Axedrez (1497).

Of central importance are the patterns themselves. If learning the names helps you learn patterns that you will see often, then they are useful. Knowing the name is not essential to perceiving the pattern. For most chess players, the name is a useful memory device.

08 July 2017

Three Tactics

A pin, decoy, and fork often work together to exploit an elementary error. Sometimes, exploitation of the error is complex, but it remains rooted in a fundamental pattern that should be well-known.

A few days ago in an online blitz game, I had this position.

White to move

I executed the pin. Rather than capturing my bishop (the decoy) and facing the resulting fork, my opponent resigned.

The pattern appeared in Greco.

White to move

Greco's game concludes: 12.Bb5 Qc5 13.Be3 Qxb5 14.Nxc7+ Kd8 15.Nxb5 1-0

This game deserves inclusion in all packages of instructive material to be used with beginners. My search of my largest database for positions with a White knight on d5, a Black queen on c6, and the move Bb5 (including all mirror positions with colors reversed) turned up well in excess of 400 games. Most led to defeat for the player whose queen was attacked, but not in every case.

I turned up this interesting position from the women's championship of France in 1931, the game Bastin -- Freeman, Paris 1931.

White to move

I posted this position in several fora on Facebook, but few responses identified the key move that begins the winning sequence.

9.b4 and the queen is trapped. 9...Qc6 10.Bb5 and Black resigned because 10...Qxb5 offer White the choice of capturing the queen--an error--or checkmating the Black king.

In Fries Nielsen -- Liersch, Germany 1980, White won Black's queen. However, Black gained more than sufficient material compensation for the queen and went on to win.

White to move

14.Bb5 axb5 15.axb5 Qxd5! 16.exd5 Rxa1 and Blkack has a rook and three minor pieces for a queen and two pawns.

05 July 2017

Blundering into Victory

On Monday, David Griffin and I met at the Spokane Valley Library to play our game in the Spokane Contenders. This six player round robin began in early May and must be completed by early August. The winner faces Michael Cambareri in the City Championship. Our game was Griffin's fifth and my first. I stated to those who asked that I would play all of my games in July.

This game was the second time that I faced Griffin's Nimzo-Larsen Attack. In the first, I opted for an attempt at tactical refutation, came out of the opening slightly worse, but then was able to gain the advantage when Griffin missed a knockout blow. I opted for a positional response this time and secured a clear space advantage from the opening. As I was playing for checkmate, I made a few errors that let my opponent crawl back into the game. He missed his chances, though, and I had a slight edge in the endgame.

Then, I blundered throwing away the game. This blunder, however, proved to be the game winning move.

Griffin,David (1523) -- Stripes,James (1841) [A06]
Spokane Contenders Spokane, 03.07.2017

1.Nf3 c5 2.b3 Nf6 3.Bb2 d5 4.e3 g6 5.Be2 Nc6 6.0–0 Qc7N

I was pleased to reach nearly the same position I had against Michael Cambareri when I beat him in seventeen moves, but with colors reversed. I contemplated whether lack of deployment of the bishop to g7 was of any account.

6...Bg7 7.Ne5 (7.d4 cxd4 8.exd4 0–0 9.c4 dxc4 10.bxc4 Ne4 and drawn in 51 moves Rethy,P [2389] -- Szabo,L [2537], Budapest 1940) 7...Nxe5 8.Bxe5 0–0 9.Qc1 Ne8 10.Bxg7 Nxg7 11.f4 Qd6 and drawn in 36 moves Trompowsky,O (2366) -- Cruz,W (2307), Rio de Janeiro 1940.

7.d3

Griffin spent twenty minutes on this move.

7.c4 d4 8.exd4 cxd4 9.Nxd4 Qe5 would have pleased me.

7...Bg7 8.Nbd2 0–0 9.h3 b5

White often plays b4 against the QID. Indeed, A row of pawns on d4, c4, and b4 occurred in several of the games I went through preparing for my Club Championship battle with Michael.

10.Nh2

I was impressed that all of White's pawns are capable of moving to the fourth rank. While it appears that I am gaining space with my pawns on the queenside, I could easily find myself in possession of a fragile center.

Black to move

10...e5

10...Bb7 11.f4 and White will post a minor piece on e5.

11.f4 d4 12.fxe5 Qxe5

12...Nxe5 would be a gross error 13.exd4 cxd4 14.Bxd4±.

13.e4

Black has more space, leading to greater mobility and flexibility. And yet, it is not entirely clear how to proceed. I would like to exploit some apparent weaknesses around the White king, but the defensive forces seem adequate. Before my queen can profitably occupy the weakened g3 square, White must commit a knight or bishop to f3.

13.exd4 Nxd4 14.Nhf3 Qe3+ 15.Kh1 Bb7 16.Bxd4 (16.Nxd4 Qxh3+ 17.Kg1 Qxg2#) 16...cxd4.

13...Be6

I didn't like 13...Qg3 14.Rf3.

13...a6 was a move that I considered, but regarded as slow. Still, it increases the mobility of my rook on a8, which could then lift to the seventh rank. It also transfers the onus of making important strategic and tactical decisions to my opponent.

14.Ng4 Nxg4

14...Bxg4 15.Bxg4 Bh6.

15.Bxg4

Black to move

15...f5

This forcing sequence left me with a weak f-pawn, but also opened the g-file for my heavy pieces. I considered 15...Qg3 16.Rf3 Bxg4 17.Rxg3 Bxd1 18.Rxd1 when it was not clear to me that I had gained anything from the material exchanges. I needed to win this game, so eschewed simplification that did not lead to clear advantage.

15...Bh6!? 16.Bxe6 Be3+ 17.Kh1 Qxe6.

16.exf5 gxf5 17.Bf3 Rac8 18.Re1 Qd6

What has become of my advantage? My forces are in retreat. And yet, I was confident that retreat was merely redeployment and that White's forces lacked coordination.

19.Nf1

19.Bxc6 seems worthy of consideration in view of the principle that a player lacking space should exchange pieces.  19...Rxc6 But, this rook will soon come to g6 and the pressure on g2 may be too much for White.

19...Ne5 20.Nh2

20.Bc1 f4 (20...Nxf3+ 21.Qxf3 Bd5 22.Bf4 Qc6 23.Qf2) 21.Nd2.

20...Rf6

20...Nxf3+ 21.Nxf3 Bd5
20...Bh6 with plans to play Be3+.

21.Bc1 Rg6

White to move

22.Kh1?!

22.Bh5! Bd5 (22...Rf6 23.Bf4+-) 23.Bxg6 Qxg6 24.Re2 Nf3+ 25.Nxf3 Bxf3 26.Bf4 and the game favors White. Black can win back the exchange, but has a weaker pawn structure.

22...Nxf3 23.Nxf3 Bd5 24.Bd2

Black to move

24...Rg3!

24...Qg3 25.Rg1 (25.Re2 Bxf3–+) 25...Re8.

25.Rf1 only move Re8

I underestimated 25...Qg6 26.Rf2 Bxf3 27.Rxf3 Rxg2 28.Qe1.

26.Be1 Rg6 27.Nh4 Re3! 28.Rf3 only move

28.Nxg6 Rxh3+ 29.Kg1 Qh2+ 30.Kf2 Qxg2#.

Black to move

28...Bxf3

28...Rge6 29.Bf2 Bxf3 30.Nxf3 Re2 was a better means of keeping control of the game.

29.Nxf3 Qd5?!

I wanted to maintain the pin on g2 with its attendant checkmate threats. I considered 29...Rge6 which would have been more logical. There is no realistic chance to find checkmate, but domination of the open file keeps White's pieces in a passive role.

30.Bf2 Re7

Again, my forces are in retreat.

31.Qf1 Bh6! 32.Re1 Be3 33.Nh4 Rge6

At this point in the game, I sensed that I had let my advantage slip away. However, Stockfish insists that my advantage is as strong as it had been at any point prior. Nonetheless, it would slip away soon.

33...Rh6 34.Nf3 (34.Bxe3 Rxe3 35.Rxe3 dxe3 36.Nxf5 Rxh3+ 37.Kg1 and what will I do about Ne7+? ) 34...f4.

34.Bxe3

Black to move

34...dxe3?

34...Rxe3 was best

a) 35.Nxf5 Rxe1 (35...Rxh3+?? 36.Kg1 Rxe1 37.Qxe1 Qxf5 38.gxh3=) 36.Nxe7+ Rxe7–+.

b) 35.Nf3 Rxe1 36.Nxe1 Qe5–+.

c) 35.Rxe3 dxe3 (35...Rxe3 I had examined 36.Nxf5 Rxh3+ 37.Kg1 Re3 38.Nxe3 dxe3=) 36.Nxf5 Re6–+.

35.Qxf5 Re5

35...Qxf5 36.Nxf5 Rf7 37.g4 e2 was not to my liking.

36.Qg4+ Kh8 37.Qc8+ Re8 38.Qg4 Rg8

38...Qd4! Black maintains a clear advantage in all lines.

39.Qf4

39.Qe2 Rf8.

39...Reg5

39...e2

40.Qf6+ R5g7 41.Rxe3

Black to move

It has become clear that not only have I squandered an advantage, but am in danger of losing.

41...Qd4?

I regretted not playing this move three moves earlier and now felt that it was forced, completely missing White's refutation.

41...a5 42.Re5 Qf7 43.Qxf7 Rxf7 44.Rxc5±
41...Qf7= with equal chances for both sides.

42.Qxd4

42.Re5±

42...cxd4 43.Re4

43.Re2 is probably equal.

43...Rc7

I still have hope of advantage with a pawn exchange because my rook also restrains the enemy king, while my own king might join the fight.

44.Rxd4 Rxc2 45.a4 bxa4 46.Rxa4

Black to move

46...Ra8

46...Rg7 was the correct way to defend the pawn, keeping pressure on g2.

47.d4 Rb2 48.b4 Kg8 49.Nf5 Kf7 50.g4 Kf6

50...Kf8 would have been a beautiful prophylactic move.

51.h4

Black to move

51...Rc8??

Right idea, wrong square.

51...Re8 52.Ra6+ Re6 53.Ra1 a6 and Black is pressing with the advantage.

52.Rxa7??

With both his rook and my pawn still in his hand, David saw the ensuing checkmate and resigned here. Having touched my pawn, he could no longer retract his move.

52.Ra6+ Kf7 53.Nd6++-.

0–1


15 June 2017

Here we go again!

Finding the study by Leonid Kubbel (see "One by Leonid Kubbel") in Tal's Winning Chess Combinations (1979), sent me back into a book that I bought last summer. Genrikh Moiseyevich Kasparian, 888 Miniature Studies (2010) contains fifteen of Kubbel's studies, as well as some background about the composer. Several of these studies feature clever combinations that provoke stalemate to save half a point for the weaker side.

Kubbel's studies are economical and practical. As he states, and Kasparian quotes:
The idea must be implemented, in the conditions of a mutual with active participation, without exception, of all pieces. Black must not wait until White fulfills his plan, but must find counrterplay, combining defense with counter-attack. All phases of this struggle--the entering into the dispute, the central stage and the end--must be connected. Each ide must be expressed using the minimum resources.
As quoted in Kasparian, 888 Miniature Studies, 71.
The idea in one that I worked through last night did not strike me as quite as compelling as in some of the others, but playing it out against Stockfish presented me with a small problem stopping a pawn, and then offered more practice with checkmate using a bishop and knight (see "Bishop and Knight Checkmate").

White to move
From Kubbel, Rigaer Tageblatt 1914.

It is clear that White must win both the bishop and the pawn without exchanges.

Stripes,J -- Stockfish (iPad)
From Kubbel, 15.06.2017

1.Be4

The pin is the only move.

1...Kxa7 2.Nd5

Setting up to attack the bishop and pawn.

2...Bg8 3.Ne7

Now, Black has many possibilities. The main difficulty of this study stems from seeing from the starting position that all Black's options here fail.

3...Bh7

3...Bf7 is given as the main solution. 4.Nc6+ Ka6 5.Bd3+ Kb7 6.Nd8+.

4.Kd6 Ka6

4...Kb8 is given in an alternate solution.

5.Ke6

Comically, it was only at this point that I became fully conscious of the direction that Black's pawn moves. In a study, White always moves first and is on bottom in the diagram. However, I solve enough exercises where the board is flipped that I sometimes need to labor to focus on which way pawns move. I have failed exercises in Chess.com's Tactics Trainer because I thought pawns were moving the wrong way.

5...Kb5 6.Kf6 Kc5 7.Kg7 Kd4

White to move

I solved this exercise on my iPad three times last night, each time trying a different move here. My qust was for a more efficient capture of Black's pawn and subsequent checkmate. I saved only the third effort.

8.Ba8

I played 8.Bb1 on the first effort. Keeping the bishop on the long diagonal seems better. This idea, adopted on my second and third tries, solved the minor problem of eliminating the pawn without exchanges.

8...g5 9.Kxh7 g4 10.Kh6

10.Nf5+ is better. As the king cannot capture the pawn, it might be better to only move it towards the center. Once the pawn is eliminated, the first step in checkmate with bishop and knight is to centralize one's pieces.

10...Ke3 11.Kg5 g3 12.Nd5+ Kf2 13.Nf4

The only winning move, but easy to see.

13...Kf1 14.Kg4 g2 15.Nxg2 Ke2 16.Kf4 Kd3 17.Ne3 Kd4

White to move

18.Be4

It has become gratifying to see over and over, when subjecting my play to computer analysis, that I played the move that lead to the fastest checkmate. Alas, later on, there were some inefficient moves.

18...Kc5 19.Ke5 Kb5

White to move

20.Kd5

20.Kd4 was best. My move adds four moves to the checkmate sequence. Why is d4 the better square?

20...Kb4 21.Kd4 Kb3 22.Bd3 Kb4 23.Bc4 Ka3 24.Kc3

Efficient and correct.

24...Ka4

White to move

25.Nd5

Here we go again. 25.Nc2 was correct. My next few moves reveal that a problem remains in my execution of the bishop and knight checkmate (see "Making my Point").

25...Ka5 26.Bd3 Ka4 27.Kc4?

Adding five moves to the finish. 27.Nc7 was correct.

27...Ka3 28.Ne3 Kb2 29.Nc2 Kc1 30.Kc3 Kd1 31.Bc4 Kc1

White to move

Finally, I have reached a position that I know how to execute efficiently.

32.Ba2 Kd1 33.Nd4 Ke1 34.Kd3 Kf2 35.Ne2 Kg2 36.Be6 Kf3 37.Bf5 Kf2 38.Bg4 Ke1 39.Ke3 Kd1 40.Bf5 Ke1 41.Bc2 Kf1 42.Nf4 Ke1 43.Ng2+ Kf1 44.Kf3 Kg1 45.Kg3 Kf1 46.Bd3+ Kg1 47.Nf4 Kh1 48.Be2 Kg1 49.Nh3+ Kh1 50.Bf3# 1–0

12 June 2017

One by Leonid Kubbel

In Tal's Winning Chess Combinations (1979) by Mikhail Tal and Victor Khenkin, each section concludes with several exercises. There are six at the end of chapter II, "The Bishop". Five gave me minimal difficulties. That is, I solved most quickly and all accurately. The sixth, however, vexed me. I looked at it several times over the course of two evenings. Finally, having given up, I entered it as a position in Stockfish on the iPad and played the side that was supposed to lose--Black. The game was drawn by repetition because I could not find a way to convert my material advantage.

The failure of Stockfish lessens my pain.* The exercise was composed by Leonid Kubbel (1891-1942).

White to move

The authors of Tal's Winning Chess Combinations offer, "it all happens in six moves" (53).


*Stockfish on my desktop computer solved the exercise in about five seconds.

11 June 2017

Rook versus Bishop

When I think that I understand something, I expect to be able to execute the maneuver in mere seconds. Sometimes, my understanding of the patterns is not strong enough. It is well-known that rook versus bishop is usually a draw, but that a few positions favor the rook. One such position is an exercise in my Essential Tactics: Building a Foundation for Chess Skill (2017).

White to move

The tactic is simple. 1.Kf6, forcing the bishop to move. But then, the finish takes me more time than I think it ought. I want to execute the moves to checkmate in ten seconds or less, but find that the calculation can require a minute or more. Each White move must contain a concrete threat of a) checkmate, b) capture of the bishop, or c) the final threat that pins the bishop on the back rank, creating zugzwang. One slip and a drawn bishop versus rook ending is reached.

In rare instances, usually with more pieces on the board, the bishop dominates the rook. This composed problem came to my notice via Mikhail Tal, and Victor Khenkin, Tal's Winning Chess Combinations (1979).

White to move

White need only check the king from a square where the bishop cannot be captured. Alas, both the immediate 1.Bh3 and 1.Bg4 fail. A zwischenzug is necessary to divert the rook from control of these squares.

30 May 2017

Making my Point

In "Bishop and Knight Checkmate," I offered some mild criticism of Kevin at thechesswebsite.com. In his YouTube video teaching checkmate with bishop and knight and repeats the phrase, "it doesn't really matter," as he emphasizes general concepts. He communicates to his viewers that moves grounded in calculation or memorized patterns are less important than general concepts.

There are three steps or phases in this checkmate.

1) centralize and drive the king to the edge,
2) drive the king from wrong corner to right corner,
3) checkmate.

General principles--centralizing ones pieces and coordinating them--do prevail in the first phase, but failure to calculate runs risks. Last night, I spent a few minutes continuing my practice of this checkmate. I started from one of the exercises that I created for my series, Essential Tactics. Two books containing these exercises are available through Amazon: the eBook Essential Tactics: Building a Foundation for Chess Skill contains the exercises and solutions; the paperback Essential Tactics: The Worksheets is designed for teachers wishing to use my worksheets with their students.

White to move

The tactic here is a simple skewer that wins the Black queen by promoting the pawn to a queen or bishop. Naturally, promotion to a queen is the sensible and correct move, unless one is seeking practice checkmating with bishop and knight.

In the course of my practice, I made many moves that tablebases reveal to be the best possible. Often there are several different moves that lead to checkmate in the minimum number of moves. However, I made several moves that were short of perfection. One move added six to the number required to bring about checkmate. Two missteps of this magnitude would have awarded the computer a draw by the fifty-move rule.

Stripes,J -- Stockfish for iPad
29.05.2017

1.h8B+ Kc5 2.Bxb2 Kb4 3.Nf3 Kc5 4.Kg2 Kb4 5.Kf2 Kc5 6.Ke3 Kb4 7.Bd4 Kb5 8.Ne5 Ka6 9.Ke4 Kb7 10.Kd5 Kc7 11.Kc5

11.Nc4 is better. Why? The knight needs to prepare to move to c7 in order to evict the king from a8. The king wants to move to c6. But, perhaps these plans are getting a bit ahead of the position. Black's king is not yet on the edge. These squares are vital for the second phase; the game is still in phase one. It is not easy to determine why 11.Nc4 is best. Tablebases indicate that it is the only move leading to checkmate in 23 moves, while 11.Kc5 is one of seven options that lead to checkmate n 24 moves.

11...Kb7

White to move

12.Ng6

12.Kd6 is one of three choices that lead to checkmate one move faster than 12.Ng6. I thought that I had found a clever route to d5, where the knight can reach c7. But, again, this stage of the game is still the first step--driving the king to the edge.

12...Kc7 13.Ne7 Kd7 14.Nd5 Ke6

White to move

We see the consequences of carelessness. My efforts to prematurely play the second phase have unnecessarily extended the first. Now, I have a single move that keeps matters under control. I failed to execute it.

15.Kc6

15.Ne3 leads to checkmate in another 20 moves. With my move, I  am further from the finish of this game than I was on move 11. There is a principle of piece coordination that might have helped me to see my way through the fog: keep the knight on the same color square as the bishop.

15...Kf5 16.Nc3

16.Nf6 takes away e4 and g4 from the king. Black's king is forced to the edge after the subsequent moves 16...Kf4 17.Kd5 Kf3 18.Ke5 Kg3 19.Ke4 Kg2 20.Kf4.

16...Kg4 17.Kd5 Kf4 18.Ke6 Kg5 19.Ke5 Kg4 20.Ke4 Kg3 21.Be3 Kg2

White to move

22.Kf4

22.Ne2 forces the king to the edge, and prepares to move the knight to g3, where it evicts the king from h1. My move also forces the king to the edge. This was the correct point in phase one to think about optimal piece placement during the second phase.

22...Kh3 23.Kf3 Kh4 24.Kf4

I should have recognized the position after 24.Ne4. 24...Kh5 25.Kf4 Kg6 26.Ng5 Kg7 27.Bc5.

24...Kh3 25.Ne4 Kh2 26.Kf3 Kh1

White to move

Now, I feel that I understand what I am doing. Having extensively practiced phase two over the past few days, it has become routine.

27.Ng3+ Kh2 28.Bf2 Kh3 29.Bg1 Kh4 30.Ne4 Kh5 31.Kf4 Kg6 32.Ng5 Kg7 33.Bc5 Kf6 34.Bd6 Kg6 35.Be7 Kh5

White to move

36.Kf5

36.Nf7 is faster per the method I had learned from Bruce Pandolfini. 36...Kg6 37.Ne5+ Kh5 38.Kg3. It is good to remain flexible.

36...Kh4 37.Bd6 Kh5 38.Bg3 Kh6 39.Ne6 Kh5 40.Ng7+ Kh6 41.Kf6 Kh7 42.Kf7 Kh6 43.Bf4+ Kh7 44.Ne6 Kh8 45.Bg5 Kh7 46.Nf8+ Kh8 47.Bf6# 1–0

Checkmate with knight and bishop took me 45 moves after the last capture. I can do better. Surely, it does matter how one plays the pieces during the first phase of this checkmate. That was my criticism of Kevin. My own errors last night make my point.

28 May 2017

Bishop and Knight Checkmate

Forcing checkmate with a bishop and knight requires piece coordination and foresight. It is the most difficult of the elementary checkmates. I remember being on the weaker side in a game on the Internet Chess Club in the late 1990s. I told my opponent, "I think this is a draw." He was convinced that it was a win, but he tried to checkmate me in the wrong corner. The game was drawn by the fifty-move rule. After the game, I looked it up. He was right and I was wrong.

Shortly after that game, I learned the checkmate through study of several key positions in Bruce Pandolfini, Pandolfini's Endgame Course (1988). Occasionally, in blitz games or against Chessmaster, I would underpromote a pawn so that I could execute this checkmate. Those instances were usually simple, as only a few moves were needed for checkmate.

I required students to demonstrate it for the Rook Award when I first created my youth chess awards. When I was teaching it regularly, I could perform it reasonably fast, but not easily. Ten years ago, however, I was persuaded by Jeremy Silman to drop it from my awards. It is excluded from Silman's Complete Endgame Course (2007) because it almost never occurs in actual play. In its place in my awards are the Philidor and Lucena rook endgame positions. There should be no question that rook endgames occur frequently and are of immense practical value. The Philidor and Lucena positions also are easier to teach.

Last year in a blitz game at the Spokane Chess Club, I underpromoted and then struggled to execute the checkmate. It had been several years since I practiced this checkmate regularly and my skills had atrophied. Success came well after the fifty-move mark. Last week, I tried the checkmate using Chess.com's "Drills" feature. Again, I struggled. To repair my deficiency, I went to YouTube and watched a video by NM Elliott Neff and another by IM Daniel Rensch. Both of these videos are excellent. After watching these videos, I succeeded with the drill quickly and easily. But, the next morning, I struggled again. Something about the knight's W pattern eluded me. Had I been more attentive during the last two minutes of Neff's video, I might have understood it better.

White to move
The W

Through the past few days, I have watched eight or ten videos, reread the relevant portions of Pandolfini's Endgame Course, and read the bishop and knight section of Karsten Muller and Frank Lamprecht, Fundamental Chess Endings (2001). I also have played out dozens of positions against Stockfish on my iPad. I have been in the diagram position above in game after game. I have played this position so often that my hand is learning the moves.


Transition to the Lock

For many years, I have had a vague memory of Pandolfini's Endgame 22, "Transition to the Lock".

White to move

1.Bg5 Ke8 2.Ng6

2.Ke6 is an easier system to remember.

2...Kf7 3.Ne5+ Ke8 4.Kc7

Black to move

When I was failing, I was always aiming at this position, but the bishop and knight swapped places in my memory. As a consequence, Black was able to shuffle the king between e7 and e8 and White failed to make progress. With these two minor pieces in their correct positions, the finish is easy.

4...Kf8 5.Kd7 Kg8 6.Ke8?!

6.Bh6 was the correct move.

6...Kg7 7.Ke7 Kg8

White to move

8.Bh6 Kh7 9.Bf8 Kh8 10.Kf7 Kh7

White to move

11.Nd7 Kh8 12.Bg7+ Kh7 13.Nf6#.


The Drill

Chess.com's drill employs the position that tablebases have identified as the one requiring the most moves to checkmate. This position is among those listed in the appendix in Fundamental Chess Endings. The engine Chess.com uses is less accurate than Stockfish on my iPad, or so it seems. With optimal play on both sides, this position leads to checkmate in 33 moves. Neither I nor the computer played the best moves.

There are three steps in the process:

1) centralize and drive the king to the edge,
2) drive the king from wrong corner to right corner,
3) checkmate.

White to move

Among the videos that I watched this week, some were better than others. One that is okay, but not to be recommended, is Kevin's from thechesswebsite.com. Through the first phase, he keeps repeating, "it doesn't matter," or similar phrases. I disagree. While slight inaccuracies in the first phase will not be the determining factor in success or failure, they can add up. When you have 50 moves to execute a checkmate that requires 33, an inaccuracy that requires four or five moves to correct can be repeated twice. The third time could be fatal. The inaccuracies through the first eleven moves here, however, add only one or two moves each to the final solution. Had the computer been more stubborn, however, checkmate might have occurred on move 40.

Stripes,J -- Computer
Chess.com, 26.05.2017

1.Ka7 Kd8 2.Bg6 Kc7 3.Nf3 Kc6 4.Bd3

Better is either 4.Be4+ or 4.Ka6.

4...Kc5 5.Kb7 Kd6 6.Kb6 Ke7

6...Kd5 resists longer.

7.Kc6 Kf6

7...Ke6 resists longer.

8.Kd5

8.Kd6 is better. Centralization is a good general concept, but should not supplant concrete analysis.

8...Kf7

8...Ke7 is more stubborn.

9.Ke5 Ke7

9...Kg7

10.Bf5

10.Bc4 is more accurate.

10...Kf8

10...Kf7

11.Kf6 Kg8

White to move

Black's king is on the edge and seeking refuge in the corner where checkmate is impossible without a dark-squared bishop. White's king is optimally placed, as is White's bishop. The knight must go to f7 to evict the king. In Neff's video, the knight gets to f7 via g5. Objectively, there is no difference between g5 and d5, but as a practical matter, it is worth remembering that the knight wants to be on the center square that is two spaces diagonally from the wrong corner. In some cases, the knight might take up this position before the bishop is posted on its ideal diagonal.

12.Ne5 Kh8 13.Nf7+ Kg8 14.Bg6

Here, in his video, Kevin states that the bishop "improves its position" ("Chess Endgames -- Bishop and Knight, Part 1"). Nonsense. The point of the bishop's move is to lose a tempo without altering the position.

14...Kf8 15.Bh7 Ke8

We have reached the position with the colored W near the top of this post. The letter W highlights the route the knight will take through the course of the second phase. Rensch offers a useful principle, "lead with the knight, follow with the king."

16.Ne5 Kd8 17.Ke6 Kc7

White to move

This was the point where I failed on the second day, earlier this week. As panic set in, I struggled to find a route to Pandolfini's position (after move 4 in "Transition to the Lock"). But, there is another lock available.

18.Nd7 Kb7

White to move

19.Bd3

This move completes the lock by covering the squares highlighted in yellow.

19...Kc6 20.Bc4 Kc7 21.Bd5

21.Bb5 pursues Pandolfini's "transition to the lock", which also works.

21...Kd8 22.Kd6

Black to move

We have a sitiuation identical in all its particulars to one that existed two squares to the right after evicting Black's king from the wrong corner. Here, the same maneuver as before drives the king back in the direction we wish.

22...Ke8 23.Be6

Losing a tempo.

23...Kd8 24.Bf7

Denying Black's return to the e-file.

24...Kc8 25.Nc5

The knight reaches the third point of the W. White repeats the process--knight moves, king follows, bishop either loses a tempo or cuts off the escape.

25...Kd8 26.Nb7+ Kc8 27.Kc6 Kb8 28.Kb6 Kc8 29.Be6+ Kb8

White to move

Now, the third and final phase. It is checkmate in four. White's only difficulty is easily solved. The knight must check the king on g8 without blocking the bishop's control of the long diagonal. Two squares are available: d7 and a6. However, d7 would allow the king to return to c8. If we had this position with Black to move, then the bishop could check first and the knight deliver checkmate from d7.

30.Nc5 Ka8 31.Bd7 Kb8 32.Na6+ Ka8 33.Bc6# 1–0

23 May 2017

Seeing Patterns

Tal's Winning Chess Combinations (1979) has influenced my perception. Last week, I read the first chapter of this book by Mikhail Tal and Victor Khenkin, which exists under several titles with and without Tal's authorship. This chapter concerns the rook and corridor checkmates and checkmate threats. These corridor vulnerabilities are most often back-rank weaknesses, but there are other corridors, including a position where a rook must be given up to avoid checkmate between two walls of pawns alongside the f-file.

The large number of deflection combinations to threaten checkmate has made me more alert to these possibilities when going through other games. Of course, these ideas are not new to me. I was familiar with the idea even before Lev Alburt's Chess Training Pocket Book (1997), which I read fifteen years ago, stimulated my imagination for the maneuvers with this exercise.

White to move

Alburt gives the exercise the title, "Defection Detection". It is number 93 in the book.

This morning, I was reading Baskaran Adhiban's annotations to his draw against Wesley So at the Tata Steel Chess Tournament in January when the deflection motif jumped into my perception. After 25.Bxa7, So could have played 25...Rxa7. He did not, playing 25...Bxc3 instead.

What if he had grabbed the bishop?

White to move

Immediately, I saw 26.Qd5+ Kh8 27.Qxe5. However, nothing compels the suicidal 27...Rxe5. So would have had choices: 27...Raa8, 27...Qb6+, and others. In Adhiban's case, his offer of a bishop wins So's bishop, but no more. The game, as he points out, was, "[a]n exciting draw with lots of interesting twists!" (Chess Informant 131, 49).

22 May 2017

Uh-Oh!

In a blitz game this morning, I had an uh-oh moment. Either I was losing my queen or a bishop. I spent 21 seconds contemplating the position, and reasoned that I had compensation for the queen. Then, in the complications, my opponent faltered. I missed some quicker checkmates, but maintained a clear advantage while pressing the attack against a vulnerable king. Most of my opponent's pieces were spectators.

Stripes,J (1845) -- Internet Opponent (1809) [D07]
Live Chess Chess.com, 22.05.2017

1.d4 d5 2.Nf3 Nf6 3.c4 Nc6 4.Nc3 Bg4 5.Ne5

5.cxd5 seems better. One hopes that I will be prepared to make this capture when appropriate should I reach a similar position OTB.

5...Nxe5 6.dxe5 Nd7

6...d4 7.Nb1 Ng8 8.Qb3 Bc8 9.Nd2 e6 Portisch,L (2575) -- Hermann,M (2405), Bad Woerishofen 1992 and drawn in 56 moves. Both players' anti-development highlight the lack of coordination of their pieces.

7.Bf4?

7.Qd4 Bf5 8.cxd5±

7.Qxd5 c6 8.Qd4 Be6 +=

7.cxd5 Nxe5 8.Qd4 f6 9.Bf4 Bc8±

7...dxc4 8.Qa4 Be6 9.e4 c6

It is clear that winning the pawn on c4 is no easy matter.

10.Rd1 Qb6

10...b5 and Black's pawn in secure.

11.Rd2 g6?!

11...Nc5 12.Qa3 Nd3+ 13.Bxd3 cxd3 14.0–0=

12.Bxc4! Nc5

White to move

13.Bxe6 (box) Nxa4 14.Bd7+ Kd8 15.Bxc6+!?

15.Bh3+ forces a draw 15...Ke8 (15...Kc7 16.e6+ Kc8 17.exf7+ e6 18.Bxe6#) 16.Bd7+=.

15...Kc7 16.Bxa4 (box)

Black to move

16...Qe6?

16...e6 was the only move, with a slight edge for Black.

17.Nd5++- Kc8 18.0–0 Bg7

18...b5 19.Bb3+-.

19.Rc1+ Kd8

White to move

20.Nf6+

Perhaps the seventh best move, but easily winning, as Black has two legal moves. One leads to checkmate on the move. The other returns the queen.

I missed the forced checkmate in eight: 20.Nc7+ Kc8 (20...Qd6 21.Ne6+ fxe6 22.Rxd6+ exd6 23.Bg5+ Bf6 24.Bxf6#) 21.Nxe6+ Kb8 22.Nd8 a5 23.Rd7 Rxd8 24.Rxd8+ Ka7 25.Be3+ b6 26.Rc7+ Ka6 27.Rxa8#.

20...Qd6

20...Qd7 21.Rxd7#

21.exd6 Bxf6

Black walks walks into checkmate in six.

21...exf6 22.Rc7+-.

22.dxe7+ Kxe7 23.Rd7+

23.Bd6+ leads to a faster checkmate, and also demonstrates understanding of bishops and rooks cooperating. 23...Ke6 24.Bb3+ Kd7 25.Ba3+ Bd4 26.Bxf7 g5 27.Rxd4#.

23.Rc7+ Kf8 (23...Ke6 24.Rd6#) 24.Bh6+ Bg7 25.Rdd7 Bxh6 26.Rxf7+ Kg8 27.Bb3 Rd8 28.Rf6+ Rd5 29.Bxd5#.

23...Ke6

White to move

Black walks into a checkmate in three.

23...Ke8 was more stubborn 24.Rxb7+ Kf8 25.Rcc7 g5 26.Rxf7+ Kg8 27.Rxf6 Rf8 28.Rxf8+ Kxf8 29.Bd6+ Kg8 30.Bb3#.

24.Rxb7 Be7 25.Rc6+ Bd6 26.Rxd6# 1–0

21 May 2017

Blunders

An appalling number of chess games are lost (and won) because a player puts a piece where it is free for the taking. Chess players use the term en prise, which no one in America pronounces correctly, when a piece is within grasp (see Edward Winter, "En Prise [Chess Term]," History Notes, updated 28 February 2015). In Essential Tactics: Building a Foundation for Chess Skill (2017), where I define such terms, I offer the following simple exercise to introduce the idea.

White to move

Such positions often arise from blunders. In a comic blitz game yesterday, it seems that neither player was looking at the board.

Black to move

Black has an extra pawn and a slightly more secure king. However, Black threw the game away with a foolish check that leaves his queen en prise.

26...Qg4+??

However, White did not snatch the free queen, even though his own queen was also undefended.

27.Kf1??

Evidently Black then noticed that the queens were in contact because he defended his queen.

27...h5??

Finally, White awoke and removed the offending queen.

28.Qxg4 hxg4

A few moves later, White won back the pawn. Nonetheless, he lost after a long battle that both players might wish to forget.

When I think of blunders, I often remember a game that I played fourteen years ago. It was my only standard rated loss to Jim Waugh, against whom I am 10-1-1. Including rapid games, my record reflects two additional losses: 25-1-3. We have played many casual games as well, and he has won a few of those. This loss in the 2003 Inland Empire Open, however, was painful, and remains fresh in my mind. I have a clear and relatively easy win.

Black to move

Inexplicably, I played 22...Re3, thinking to drive the queen from defense of his vulnerable king. Once he had the upper hand, Waugh did not let up.

16 May 2017

Develop Your King

In one of my many blitz games this morning, I had one of those many experiences when I realized that I was playing poorly and now seemed to be losing material.

Stripes,J (1806) -- Internet Opponent (1852) [D06]
Live Chess Chess.com, 16.05.2017

1.d4 d5 2.c4 Nf6 3.Nc3 Bf5 4.Bf4 e6 5.Nf3 Nc6 6.e3 Nb4

White to move

In my despair, I remembered the words of Wilhelm Steinitz:
[W]e consider it established that the king must be treated as a strong piece both for attack and defence. This means that so far from requiring great protection early in the game a few simple precautions which we shall further explain, will render him so safe that any attampt at attacking his wing will be more dangerous for the opponent than for himself.
Wilhelm Steinitz, The Modern Chess Instructor (1889).
Steinitz was concerned with the king's role in self-protection on the king's side, when the king itself is the target. My opponent was angling for my rook, winning an exchange.

7.Kd2! Bc2

My opponent might have tried 7...Ne4+ 8.Nxe4 dxe4 9.Ne1 (9.Ne5? f6)

8.Qc1 Ne4+ 9.Nxe4 dxe4 10.Ne1

Black to move 

10...Nd3

10...Ba4 seems to be a better effort to take advantage of the king in the center.

a) 11.a3 Nc6

11...Nd3 is as in the game 12.Nxd3 exd3 13.Bxd3 f6 White has a one pawn advantage.

a1) 12.Bg3 (12.Qc3 e5 appears dangerous). 12...e5 13.d5 Na5 and White is losing at least an exchange.

a2) Nc2

b) 11.b3 is probably safest.

11.Nxd3 Bxd3 12.Bxd3 Bb4+ 13.Ke2 exd3+ 14.Kxd3

Black to move

14...0–0 15.a3 Be7 16.Rd1 f6 17.Ke2 Qe8 18.Bg3 h5 19.h4 and I went on to win the endgame.