28 June 2016

Calculate

In pawn endings, a rook pawn (a- or h-pawn) usually draws. There are exceptions. While reading about these exceptions this morning in Muller and Lamprecht, Fundamental Chess Endings (2001), I suddenly remembered a game from last summer. From this position, I saw clearly the next ten moves or more.

Black to move

24 June 2016

Rule of the Square

Earlier this week, I taught a class called "Six Most Important Pawn Endings" in Inland Chess Academy's June chess camp. I sought to highlight six principles that occur with some frequency. The rule of the square, also called the square of the pawn, was one of these principles. The basic illustrative position is presented in my post "Simple to Complex" (June 2012). There is further discussion in "Square of the Pawn" (January 2014).


In the camp, I also presented an illustrative position from a recent online blitz game where an ill-advised capture transformed a simple draw into a simple win for the opponent.

White to move

Despite an extra pawn, Black can make no progress without help. Almost any move here holds the draw. However, my opponent played the inexplicable 57.Rxg5?? Perhaps he was frustrated that I was playing on in a dead draw after he had offered a draw.

57...Rb6+ 58.Kf5 Rb5+ 59.Kf4 Rxg5 60.Kxg5

White's king is outside the square.

Black to move

61...a5-+.

Today, in a 15 10 game online, a different opponent missed a draw through failure to recognize the rule of the square.

White to move

I played 28.h4 because creation of a passed h-pawn seemed my best chance for advantage in this opposite color bishops ending. As Black's kingside pawns are on light squares, the bishop has difficulty stopping the pawn. Indeed, a few seconds of calculation confirmed that Black's bishop will fail.

28...Be8?

28...Kd7 or Kd8 stops the future passed pawn by moving into the square.

29.f5 gxf5?

29...exf5 30.gxf5 Kd7 should hold.

30.gxh5??

30.h5+-

30...exf5 31.Kf4 Bd7?

31...Kd7 was still possible

32.h5+-

Black to move

Perhaps my opponent saw this position a few moves back and found a way for his bishop to cover h8.

32...f6 33.exf6

I spent over one minute on this move. It was clear that the bishop cannot stop both pawns, but the king is in the square of the f-pawn. Alas for Black, the tempi that must be spent by the bishop leave the king unable to participate.

33.h6 was sufficient, however.

33...Be6 34.h6 Bg8 35.f7 1-0

With an overworked bishop, my opponent resigned.

10 June 2016

Ne2?

Last weekend I played in the Spokane Contenders, a round robin tournament that determined the challenger to our city champion. I had won this tournament in 2008 and 2012. I also tied for first in 2010, finishing second on tie-breaks. I played again in 2014, but my play was mixed and I finished in the middle.

My play was mixed again this weekend. I won my first round game on the Black side of a Ragozin--the first time I had played this opening in over-the-board play. I had been reading The Ragozin Complex (2011) by Vladimir Barsky and practicing the opening in some online blitz (see "Opening Inaccuracy" [2014]).

On Sunday, I played a long and interesting game against a former student, a three-time elementary state champion finishing his sixth grade year. He is growing accustomed to beating the A Class players who occupy the top tier of players in my city. In round three, he beat the player I had defeated in round one. We played a long game that ended in a draw. After he offered a draw on move 46, I tortured him as long as I could, struggling in vain to provoke an error. I had trained him well in the endgame and he refused to crack. After twenty moves of probing, I exchanged my rook for his bishop and advanced pawn and we played out the dead drawn pawn ending rapidly until stalemate on move 79.

Then, in round five, I misplayed a Sicilian Kan in the same manner that I have done in the past and was essentially lost by move eleven. I played another fourteen moves attempting tricks, all of which failed.

In the second round, Saturday afternoon, I played the lowest rated player. I had beaten him in all of our prior encounters and sat at the board with confidence. We quickly reached a familiar tableau.

Stripes,James (1811) -- Frostad,John (1608) [D18]
Spokane Contenders Spokane (2), 04.06.2016

1.Nf3 d5 2.d4 Nf6 3.c4 c6 4.Nc3 dxc4 5.a4 Bf5 6.e3 e6 7.Bxc4 Bb4 8.0–0 0–0

White to move

9.Ne2?

In 2007, I played 9.Qe2 against my phone, a RAZR running Chessmaster. I won that game easily. I also played 9.Ne2 once before in a correspondence game that I lost after a long struggle.

Perhaps the question mark is not fully warranted. Several strong Grandmasters have played this move, although the highest rated Black player who has lost is Rok Hrzica 2296.

The central problem with this move is that it wastes tempi, conceding the initiative to Black. In the game, I not only expended several tempi to gain the bishop pair, but also failed to attend to the needs of my bishop on c4 and hence did not continue with a pair of bishops into the middle game.

9...Nbd7 10.Ng3 Bg6 11.Nh4

Both 11.Bd2 and 11.b3 seem a little better.

11...c5 12.Nxg6

12.f4 was played in Bogoljubow,E -- Alekhine,A, London 1922, which was drawn in 70 moves.

12...hxg6 13.Qf3

13.dxc5 is probably best 13...Nxc5 (13...Ne5 and drawn in 58 moves,.Piket,J (2670) -- Shirov,A (2710), Aruba 1995) 14.Qe2 Nfe4 and Black went on to win a long struggle Rubinstein,A -- Alekhine,A, London 1922.

13...cxd4 14.exd4 Nb6

White to move

15.Qb3?

15.Bb3 keeps the prospect of maintaining a bishop pair alive. White is already suffering for his errors. Black's pieces are mobile and coordinated. Black's plan to eventually win the isolated d-pawn is simply and straightforward. Meanwhile, my only effort to generate counterplay hinged on a mating attack employing either quuen and knight against f7 (easily stopped) or creating a battery of heavy pieces on the h-file (nearly impossible).

15...a5

15...Qxd4 and Black is clearly better.

16.Rd1

16.Be3

16...Nxc4 17.Qxc4 Nd5 18.Bd2 Qb6 19.Bxb4 Nxb4 20.Ne4

20.Rac1

20...Nd5 21.Qe2 Rac8 22.Nc5 Rfd8 23.Qf3 Qc6 24.Nd3 Qb6 25.Ne5 Nf6 26.g4?

Black to move

26...Rc7

26...Rxd4! 27.g5 Rxd1+ 28.Rxd1 and White can consider resigning.

27.Rac1

27.g5 would at least be consistent with my desperate plan to go all in for checkmate. Of course, Black maintains an advantage and a comfortable game.

27...Rxc1 28.Rxc1–+ Qxd4 29.Qg3 Nd5 30.Nf3 Qxb2 31.Rd1 Qc2 32.Rd2 Qxa4 33.Qh4 Qa1+ 34.Kg2

Black to move

34...f6

34...Nf4+! wins more quickly, as I showed my opponent after the game. 35.Kg3 Rxd2 36.Nxd2 f6 37.g5 (37.Kxf4 g5+) 37...e5-+.

35.g5 b5 36.Nd4 Kf7 37.Qh3 Nf4+ 0–1

Frostad's play was solid enough to let me self-destruct. He went on to win the event and gets to play the city champion is a four game match in August. He is the second lowest rated player to play in our city championship (see "Fifteen Minutes"). I wish him well.

The loss of time with the Ne2 maneuver is a feature that I note with some frequency in my lessons with young students. Once these young players reach the point where they can understand three move tactics and are ready for complete games, we go through the eighteen games that Paul Morphy played in the First American Chess Congress. In his first game, James Thompson wasted time playing Ne2. His plan was grounded in a tactical shot aimed at the f5 square. Morphy calculated the tactics one move deeper and gained a clear edge via a zwischenzug.

Thompson,James -- Morphy,Paul [C50]
USA–01.Kongress New York (1.1), 1857

1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.d3 Nf6 5.Nc3 h6

White to move

6.Ne2 d6 7.c3 0–0 8.h3 Kh8 9.Ng3 Nh7 10.Qc2

White's play is grounded in the belief that Black's intent to push f7-f5 fails tactically.

10...f5!

Morphy understood both Thompson's plan and the tactical refutation.

11.exf5

Black to play

11...d5

The zwischenzug.

12.Bb3 e4 13.dxe4 dxe4 14.Ng1 Ne5 15.Be3 Nd3+ 16.Ke2 Bxe3 17.fxe3 Qh4 18.Nxe4 Qxe4 19.Qxd3 Qxg2+ 20.Kd1 Bxf5 21.Qe2 Qxh1 0–1

There is a moral to this story. If I insist on making the sort of moves that I teach my young students to avoid, I will lose. Regular readers may recall another tragicomic loss when I failed to heed a lesson from a familiar Morphy game (see "Knowing Better").

09 June 2016

Max Judd's Draw Claim

Mikhail Chigorin threatened to leave the tournament. Max Judd had demanded, seemingly within the rules, that Chigorin checkmate him within fifty moves. Fifty moves had transpired and Judd had claimed the draw. Along the way, Chigorin had missed a simple win and Judd had missed a line offering stronger prospects for equality.

At the end of the fifty moves, Judd's position was clearly worse. The umpire ordered Judd to continue, but he refused. The game was adjourned while the umpire considered his decision.

The umpire initially ruled in favor of Judd, then the decision went to a jury for reconsideration. The jury confirmed the umpire's decision, but Chigorin then appealed to a panel of judges. During this battle Chigorin lost a game to James Mason on time for refusing to appear at the board during the day's second playing session. On appeal, the judges reversed the umpire's position and ordered the game with Judd continue. The whole process took several days.

William Steinitz offers a synopsis of the final result in The Book of the Sixth American Chess Congress (1891).
Mr. Judd stated afterward that he played the greater part of this ending in reliance on his having the legal right of claiming a draw if he could only extend the game to fifty moves after he had claimed the count without being mated. Having accomplished his object he refused to go on with the game, which he might have done under protest without damaging his rights. But his interpretation of the rule was not sustained on appeal, and Mr. Judd was also adjudged to have forfeited the game on the ground that he did not abide by the decision of the umpire to proceed with the same. (33)
The best account of the full controversy that I have been able to locate is in Stephen Davies, Samuel Lipschutz: A Life in Chess (2015). Lipschutz was one of the players at the Sixth American Chess Congress in New York in 1889. Davies, who tells the story based upon the tournament book, the New York Times, and The Sun, offers specifics. The game was played on Saturday, 30 March 1889. The umpire's decision on behalf of Judd and the jury's confirmation of this decision took place on Monday. According to Davies, the judges were reported as overturning the decision on Thursday, 4 April. The game resumed on 13 April. Both players refused to play, but Judd's clock was started. When his time expired, Chigorin was awarded the win.

Two versions of the Fifty Move Rule existed in the 1880s. The Sixth American Chess Congress employed the rule as printed in the Book of the Fifth American Chess Congress (1881). Following the Chigorin -- Judd dispute, according to Davies, the judges and players agreed that the rule observed in the London 1883 tournament would be enforced for the balance of the event. The London rule, which is the precursor to the rule today, resets the count with each pawn move or capture.

In The Book of the Sixth American Chess Congress, Steinitz also points out Chigorin's easy win and Judd's missteps.

After 46.a4, Judd requested the fifty move count begin.

Black to move

46...b6 47.b3 a5

Steinitz observes:
Black impetuously throws away a sure win in a short number of moves. He could easily gain the opposition and throw the onus of moving on the opponent by 47...Kf4 48.Kh3 Kg5 49.Kh2 Kg4 White's pawn moves on other wing could then be easily exhausted, and Black's King would gain entrance at g3, followed by ...h4-h3, winning easily. (33)
His analysis baffles me. Why 47...Kf4? Why not the immediate 47...Kg4?

48.bxa5 bxa5

White to move

49.b4!

Steinitz speculates that Chigorin had overlooked this move. Black still has an advantage, but White's drawing prospects have improved dramatically after Chigorin missed 47...Kg4, or even Steinitz's suggestion to the same effect.

49...axb4 50.a5 b3 51.a6 b2 52.a7 b1Q 53.a8Q

Black to move

Black can win if the c-pawn successfully advances or if the queens can be swapped. To accomplish either, the Black king needs refuge from checks.

53...Qb5

Chigorin guards the c-pawn with the intention of walking his king over to the queenside where it may employ the pawn as a guard, and perhaps walk together towards c1.

Steinitz suggested that 53...Qg6 was "better adapted to keep everything safe and to lead the King over to the queenside" (33). My engines, including one running with tablebase support, find 53...Ke4 best, but otherwise concur with Steinitz.

I tried playing this position against Stockfish 7 beginning with 53...Qg6 and was not successful at avoiding a draw. It is one thing to play such a position correctly when you can see more than four million positions per second and quite another to work it out as a human. Of course, two humans facing one another are equally ill-equipped.

54.Qg8+ Kf4 55.Qd8 Kg4 56.Qd7+ Kg5 57.Qg7+

Steinitz asserts that 57.Qd8+ was better, but Stockfish 7 sees no difference between this move and the text.

57...Kf5 58.Qf7+ Ke4 59.Qf3+ Kd4 60.Qf2+ Kc3

White to move

61.Qe1+

Steinitz suggests:
Simply capturing the h-pawn that hampered the advance of his King, gave him much better prospects of drawing, as Black's c-pawn could not advance far without giving White again many checking opportunities that would have impeded its progress. (33)
However, the engines find Judd's move best. Capturing the h-pawn changes the evaluation to nearly -2.00, but playing out the suggested engine moves leads to repetition once the c-pawn begins to advance.

Even the engines do not find it a simple matter to deliver a win with Black.

61...Kb2 62.Qd2+ Ka3

White to move

63.Qe3+
As a rule in such positions, the closer to the adverse King the checks are given the more effective they are. 63.Qc3+ was the right play, and whatever Black might do either the checks would continue or the adverse Queen could only interpose in a manner that left his c-pawn unprotected, which gave additional chances of a draw for White. (Steinitz, 33)
This principle is worth remembering.

63...Ka4 64.Qd4+ Qb4 65.Qa7+ Kb3 66.Qe3+ Qc3 67.Qb6+ Kc2 68.Qf2+ Kd3 69.Qf3+ Kd2 70.Qf4+ Kd1 71.Qf1+ 

71.Qxh4 is no good. 71...Qe5+ 72.Kh3 c5 and with the pawn one square further towards promotion, White's drawing prospects diminish.

71...Kd2 72.Qf4+ Ke2 73.Qe4+ Kd1 74.Qf3+

Black to move

74...Kc2

As Steinitz notes, Black's king is now out of position for exchanging queens. The resulting pawn race would give both players queens once again, but this time with an easy draw.

75.Qf2+ Kc1 76.Qf1+ Kb2 77.Qf2+ Qc2 78.Qb6+ Ka3 79.Qa5+ Qa4 80.Qc5+ Kb3 81.Qe3+ Kb4 82.Qd2+ Kb5 83.Qb2+ Qb4 84.Qe2+ Kb6

White to move

85.Qe3+?

85.Qe5 was White's best chance, according to the engines. Now, matters are finally beginning to return to a clear advantage for Chigorin. After 85.Qe5, 85...c5 would concede the draw.

85...c5!

The pawn can now advance. Black's queen and king are now well coordinated to assist the pawn with an advance of one square every half dozen moves or so.

86.Qe6+ Ka5

A necessary finesse. The point is to move the king to b5 when the White queen cannot check from the rear.

87.Qa2+ Kb5 88.Qd5 Qf4+

The queen's mobility along the fourth rank is a critical element.

89.Kh1 Kb4

White to move 

Now, White can again check from the rear, but these checks only delay the pawn's advance. They can no longer prevent it.

90.Qb7+ Kc3 91.Qg7+ Qd4 92.Qe7 c4 93.Qa3+ Kd2 94.Qb4+ 

Black to move

94...Ke2

94...Kc1 leads to a quicker win. 95.Qa3+ Qb2

95.Qb5 Kd2 96.Qb4+ Qc3 0–1

At this point, Judd's fifty move count having been reached, he refused to go on. The dispute began. When he originally asked for a draw, his position was lost. However, Chigorin missed an easy win and overlooked White's resource on the queenside. In the ensuing maneuvering, Judd made a couple small inaccuracies.


The Rules

The Rule from the Fifth American Chess Congress
If, at any period during a game, either player persist in repeating a particular check, or series of ckecks, or persist in repeating any particular line of play which does not advance the game; or if "a game ending" be of doubtful character as to its being a win or a draw, or if a win be possible, but the skill to force the game questionable, then either player may demand judgement of the Umpire as to its being a proper game to be determined as drawn at the end of fifty additional moves, on each side; or the question: "Is, or is not the game a draw?" may be, by mutual consent of the players, submitted to the Umpire at any time. The decision of the Umpire, in either case, to be final. 
And whenever fifty moves are demanded and accorded, the party demanding it may, when the fifty moves have been made, claim the right to go on with the game, and thereupon the other party may claim the fifty move rule, at the end of which, unless mate be effected, the game shall be decided a draw.
Charles A. Gilberg, The Fifth American Chess Congress (New York: Brentano's Literary Emporium, 1881), 167-168.
Judd would seem to have staked his claim on the language: "if 'a game ending' be of doubtful character as to its being a win or a draw."

The British Chess Association Rule printed in the book of the London International Chess Tournament 1883
A player may, at any time, call upon his adversary to mate him within fifty moves (move and reply being counted as one). If, by the expiration of such fifty moves, no piece or pawn has been captured, nor pawn moved, nor mate given, a draw can then be claimed.