Sunday, November 19. 2006
Author: nabla
Extinction Chess (official rules here) is one of the most fascinating chess variants. It comes from a very natural enhancement of the goal of the chess game, in that one wins by extincting one species in the opponent's pieces - for instance capturing both knights. With such a phrasing, standard chess can be defined as a kind of restricted Extinction Chess, where only the king's species is taken into account - you certainly know that the goal of chess is to extinct the opponent's king ! This variant manages to be in the same time different enough from standard chess in order to produce a lot of new ideas, but close enough as to keep the most positional features of chess, like pawn structures and space. A game where the chess skills are highly transposable, yet where it is vital to stay fully aware of the additional dangers.
Although it is not only a deep game, but also a very fun game, Extinction Chess is less popular on Brainking that I would have expected. I don't know the reason why, and am taking profit of this column to advocate this variant by annotating in detail one of the two best games I ever played. My opponent played it very well too, equalizing as Black, and then only failing to risk himself into an unpredictable position and falling into a passive one as the result of that choice. The game illustrates how easily an Extinction Chess is unbalanced, and how hard it is to overcome the slightest inaccuracies.
Remark about the notation
Although the rules of Extinction Chess state that there is no check or checkmate, I still find it to be a big help to add the check (+) and checkmate (#) symbols to the game notation, with the meaning that :
- A check is a threat to one of the opponent's pieces, which is the last of its kind - such a piece is to be considered as a royal piece as its loss would lose the game.
- A checkmate is an unstoppable such threat. Typical Extinction checkmates are double attacks on two last pieces (those are called forks), and attacks on one last piece, whose move would uncover another last piece (those could be called pins, but I prefer to call them skewers). And it is of course also possible to mate a piece in the good old-fashioned way, attacking it in such a way that it has no retreat.
The game : nabla - xabiron, Brainking, 2006
After 2.c2-c4
The "extinction queen gambit".
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1.d2-d4 d7-d5 2.c2-c4 See the first diagram. 2...e7-e6 This is probably the most solid defense to the queen pawn opening. Unlike in standard chess, the extinction slav defence (2...c7-c6) is not solid at all - because White would play the exchange variation and get a fierce attack using the c-file - and the queen's gambit accepted (2...d5xc4) is conceding too much space. An interesting alternative is the Albin countergambit (2...e7-e5!?).
3.Nb1-c3 Ng8-f6 4.Bc1-f4 What would be a rather quiet move in normal chess is the most aggressive try here, striving to place a rook on the c-file for an early queenside attack.
4...Bf8-d6 At Extinction Chess, each piece trade is a very important change in the position, because with it in each camp one piece becomes the last of its kind. Here, at first glance the bishop trade seems dangerous for Black, because his bishop on c8 is more open to attack than White's bishop on f1. But Black correctly estimated that his resulting advance in development would be enough a compensation.
More awkard would have in fact been 4...c7-c5 , which would have been a good move if the white bishop was not on f4 : 5.c4xd5 e6xd5 6.d4xc5 (6.e2-e4!? is also a dangerous option.) 6...Bf8xc5?? 7.Bf4xb8! Ra8xb8 8.Qd1-a4+ Bc8-d7 9.Qa4-h4+ and wins, the last black knight being pinned against the black queen.
5.Bf4xd6 5.Qd1-d2 may be stronger. After 5...Nf6-e4+ 6.Nc3xe4 d5xe4 7.c4-c5! Bd6xf4 8.Qd2xf4 , Black cannot capture on d4 because of his weakness on c7. So he plays 8...f7-f5 and despite a more active queen (which is usually good in Extinction Chess), it is hard to say whether White really has an edge here.
5...Qd8xd6 6.c4-c5+
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After 6.c4-c5+
Where should the black queen go ?
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6...Qd6-e7! Black is correctly assessing that his position is perfectly sound, and that he doesn't need to seek adventure. 6...Qd6-a6?! is tempting, with the idea to pin the e2 pawn (the bishop of f1 is last of his kind), thus retarding White's development, and forcing White to keep an eye on queen checks on a5. However, after 7.Qd1-d2! Black will be in trouble trying to counter both Qd2-f4 (attacking c7) and Ra1-c1 followed by c5-c6! with an opening of the c-file.
7.Qd1-d2 The white queen will be trying to induce some weaknesses on Black's kingside. 7.Ra1-c1 would be the logical move, but the direct attack does not succeed, and there is a risk that Black will open the center to his advantage with e6-e5. For instance : 7...0-0 8.Nc3-b5 Nb8-c6 9.Qd1-d2 Nf6-e8! cuts out the possibility of Nb5-d6, after which 10...e6-e5 will follow. On the other hand, 7.Ng1-f3 would make the white knights vulnerable too early, and would allow 7...Nf6-e4 8.Ra1-c1 Qe7-f6 9.Nc3xe4+ d5xe4 10.Nf3-g1 e4-e3 11.f2-f3 0-0 when Black stands better - the direct threat is Rf8-d8xd4.
7...0-0 Not 7...e6-e5? 8.Qd2-g5! h7-h6+ (otherwise 9.Nc3xd5+!) 9.Qg5xg7 Rh8-h7+ 10.Qg7-g3 e5xd4 11.Nc3xd5+! Nf6xd5 12.Qg3-g8# winning Black's king or bishop. But now White has to do something against e6-e5. 8.Qd2-g5 h7-h6+ 9.Qg5-h4 b7-b6!
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After 9...b7-b6!
Black is threatening to take the initiative.
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Now that the white queen has chosen the kingside, it is Black who can attack on the queenside ! The threat is not so much to win a pawn than to activate the queen on b4 afterwards, which would put White under a lot of pressure. The key feature is really that Black would be "a queen up" on the queenside. 9...Rf8-d8 instead would leave White with enough time to coordinate himself ; after 10.0-0-0 e6-e5 11.d4xe5 Qe7xe5 12.Ng1-f3+ it is hard for the black queen to find a good square, for instance 12...Qe5-e6 (12...Qe5-f5 13.g2-g4) 13.Qh4-f4!
10.e2-e4!? This is a rather drastic move, but played with no further ambition than to sacrifice a piece for a perpetual check.
In Extinction Chess, White's advantage is all but negligible ; that White is going for a draw after only ten moves means that Black's opening has been a total success ; and indeed, Black is doing fine in all other lines :
- White could also react on the queenside with 10.b2-b4 a7-a5 11.b4-b5!? b6xc5 12.b5-b6 c7xb6 13.Ra1-b1 Nb8-d7 14.Nc3-a4 Ra8-b8 15.Ng1-f3 Qe7-d6 with a compensation that may not be enough.
- 10.Ra1-c1 is again the most natural move, expecting to take profit of the line opening on the queen side. But after 10...b6xc5 11.d4xc5 Qe7xc5 12.Qh4-f4 e6-e5+! 13.Qf4xe5 Rf8-e8+ 14.Qe5-f4 Qc5-b6 Black has consolidated ; if White insists with 15.Nc3-b5? , then 15...Re8-e4+! 16.Qf4-g3 Qb6xb5 17.Rc1xc7+ Bc8-f5 and the black bishop escapes.
- 10.Nc3-a4?! e6-e5! 11.Ra1-c1 b6-b5 12.Na4-c3 c7-c6 would leave the initiative to Black.
10...Qe7-d7? Black's only mistake in the game is this seemingly solid, but too passive move !
It was a must to accept White's challenge by 10...d5xe4 11.Nc3xe4 g7-g5+! 12.Ne4xg5! (White was losing a piece anyway) 12...h6xg5 (Going for the pin does not work : 12...Nf6-h7? 13.Qh4-e4 Qe7xg5 14.Qe4xa8 Bc8-d7 15.c5-c6+! winning Black's bishop or rook) 13.Qh4xg5+ Kg8-h8
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Variant 10...d5xe4, after 13...Kg8-h8
Can White try for more than the perpetual check ?
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If we had come to this position, I would probably have delivered perpetual check by 14.Qg5-h4+!, when the black knight stays pinned against the queen.
Instead, 14.Ra1-c1!? (with the idea Rc1-c3-h3#) is a possibility to play for a win, which is certainly not easy to refute. But it is a quite sound principle in Extinction Chess to consider that any piece sacrifice which does not lead to a forced win as being in fact losing. Indeed, playing with one less piece also always involves playing with one more vulnerable piece, which is not really available for the attack - here the knight on g1. So in this position, refusing the perpetual check is probably too optimistic, although...
The probable continuation would be 14...Rf8-g8+ 15.Qg5-h4+ Kh8-g7 16.Rc1-c3 e6-e5! (Otherwise, 17.Rc3-f3 would win the knight back ; 16...Kg7-f8 is a bit too clever and fails to 17.Rc3-f3 Rg8-g6 18.Rf3xf6 Kf8-g7 19.Qh4-e4 and White wins) 17.Rc3-e3!? (17.d4-d5 backfires : 17...e5-e4 18.d5-d6+ Qe7-e5 19.c5xb6? Rg8-h8# and not the black king, but the white queen gets mated ! ) and now it is not easy for Black to solve all of his problems.
At least the direct counter-attack by 17...Qe7-e6? fails : 18.Re3xe5+ Qe6xa2 (Threatening an exceptionnally nasty check on the first rank) 19.Re5-g5+ Kg7-f8 20.Rg5xg8+ Kf8xg8 (20...Nf6xg8 21.Qh4-d8#) 21.Qh4-g3+ Kg8-f8 22.Qg3xc7+ Bc8-f5 23.Qc7-b7# (mating the black rook).
But instead, 17...Rg8-h8+ 18.Qh4-g5+ Kg7-f8 19.Re3xe5+ (19.d4xe5 Rh8-h5+ 20.Qg5-g3 Nf6-g4) 19...Qe7-d8 is probably the way to go for Black.
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Main line, after 10...Qe7-d7?
The cards are now in White's hands.
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Let us go back to the game after Black played the too safe 10...Qe7-d7?
11.c5-c6+! Pawns have a very moderate value in Extinction Chess. Instead of winning one, White will be sacrificing two of them, finding it to be the only way to keep the initiative :
-11.Ra1-c1 allowed 11...c7-c6! and White is stopped : if 12.Nc3-b5? c6xb5 13.c5xb6+ Bc8-a6 14.Rc1-c7+ Qd7-d6 15.e4-e5+ Qd6-b4+ remaining one piece up.
-With 11.e4-e5 Nf6-e4 12.Nc3xe4 d5xe4 13.Qh4xe4 c7-c6 White would have won a pawn, but Black would be safe for quite some time because the pawn on e5 blocks the diagonal h2-b8.
11...Qd7xc6 11...Nb8xc6 12.Ra1-c1 would be even more awkward for Black's minor pieces, for instance 12...Nc6-e7 13.Nc3-b5 c7-c6 14.e4-e5 Ne7-f5+ (14...Nf6-e4 15.Nb5-d6+) 15.Qh4-h3 Nf6-e4 16.Nb5-d6+! Ne4xd6 17.e5xd6 Nf5xd6 18.Qh3-a3+ Nd6-e8 (18...Nd6-b7 19.Qa3-a6#) 19.Rc1xc6+! Bc8-b7 (19...Qd7xc6 20.Qa3-e7#) 20.Qa3-c3 and the threat of 21.Rc6-c7# is unstoppable.
12.Ra1-c1 Nf6xe4 The best move, taking profit of the temporary pin on the c-file. If 12...d5xe4?! 13.Qh4-f4 and Black cannot stop the opening of the c-file anymore : 13...Nf6-h5+ 14.Qf4-e5 g7-g6 15.Nc3-e2+! Qc6-a4 16.Rc1xc7+ Bc8-a6 17.Rc7-c3 followed by 18.Rc3-a3+ and the lone black bishop will soon be captured.
13.Qh4-f4 Lifting the pin by protecting the Rc1. 13...e6-e5+ Getting the c5 square for the knight and blocks the diagonal h2-b8... but only temporarily ! The other way was 13...g7-g5+ 14.Qf4-e3 Ne4xc3 15.Rc1xc3+ Qc6-d6 16.h2-h4! and Black will not be able to plug all holes in his position. 14.d4xe5 g7-g5+ 15.Qf4-e3 With dreadful threats along the c-file, where Black's last bishop resides. 15...Ne4-c5 Once again, the toughest defence ; if 15...Ne4xc3?! 16.Rc1xc3 Qc6-d7 (16...Qc6-b7 makes no difference) 17.Qe3-c1! c7-c5 18.Rc3xc5+! b6xc5 19.Qc1xc5 Bc8-b7 20.Qc5-b4# , skewing both of Black's last minor pieces.
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After 15...Ne4xc5
A small combination is called for.
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16.Nc3-e4! This showy move is also the fastest way to win. It is not complicated at all, but one could very easily overlook it !
16.b2-b4 seems to win as well, but with a bit more to calculate : 16...d5-d4+ 17.Qe3xd4 Nc5-e6+ 18.Qd4-e3 Rf8-d8 19.Nc3-b5+ Qc6-b7 20.Nb5-d6+! Rd8xd6 21.e5xd6 c7-c6 22.h2-h4 Qb7-d7 23.Qe3-e5 when Black is completely boxed in, and White can win in numerous ways.
Much weaker would be 16.Nc3-b5? d5-d4! 17.Nb5xd4+ Qc6-d5! and Black is back in the game : 18.b2-b4 Nc5-a6 19.Nd4-b5 c7-c6 20.Nb5-d6+ Bc8-e6 and the black bishop is still alive.
16...d5xe4 16...Qc6-a4 loses outright to 17.Ne4xc5+ Qa4-b4+ 18.Ke1-d1 b6xc5 19.Rc1xc5 c7-c6 20.Rc5xc6+ Nb8xc6 21.Qe3-c1# (skewer on the last knight and the last bishop). 17.Rc1xc5+! It has been told at move 4 that White's plan was to attack along the c-file. He certainly succeeded in doing so ! 17...Qc6-b7 The only move. The rook cannot be captured because of 17...b6xc5 18.Qe3-b3+ Nb8-d7 (the only square) 19.Qb3-h3+ , again skewing both last minor pieces. More over, Black cannot allow a white queen on e4 : 17...Qc6-d7 18.Qe3xe4 c7-c6 19.Rc5xc6+! Bc8-b7 20.e5-e6+! f7xe6 21.Qe4-e5+ Nb8xc6 22.Qe5-b5#
18.Rc5-c3 Now Black has one free tempo to parry the threat of 19.Qe3-c1! c7-c5 20.Rc3xc5+!, which would soon win one of Black's minor pieces. 18...Bc8-f5
Here 18...Bc8-e6! seems to be a tougher defence, but White's attack is still overwhelming : 19.h2-h4 Qb7-d5 20.h4xg5 Qd5xe5 21.Rh1xh6+ f7-f6 (21...Be6-c8 22.f2-f4+ Qe5-e7 23.Rh6-c6 wins) 22.g5xf6 Rf8xf6 23.f2-f4+! with a pretty win - Black's rook and pawn are both pinned, so that White's pawn is immune.
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After 18...Bc8-f5
Both of Black's minor pieces will soon be in big trouble.
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19.e5-e6! The reopening of the h2-b8 diagonal effectively ends the game ; Black can do nothing against the threat of 20.Qe3-g3. It should be said that 19.h2-h4 Qb7-d5 20.h4xg5 Qd5xe5 21.g5xh6 would most probably also win, for instance 21...Bf5-h7 22.Rh1-h5+! Qe5xh5 23.Qe3-g3+ Kg8-h8 24.Qg3xc7#
19...Qb7-d5 Covering c7 doesn't work : 19...Rf8-c8 20.Qe3-d4! and now that the defence 20...f7-f6 is not possible any more, the black bishop is in deadly trouble and can't escape the white queen for long.
20.Qe3-g3 and Black resigned.
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The final position (after 20.Qe3-g3)
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The threat is 21.Qg3xc7# mating the black knight, and the only way to open a square for this knight is 20...b6-b5. The conclusion would then be 21.Rc3xc7 (threatening to attack Black's queen and knight in the same time by Rc7-c5 or Rc7-d7) 21...Nb8-a6 22.Rc7-d7+ Qd5-c5 23.Rd7-d6+ Na6-b4 (or 23...Na6-c7 24.Rd6-c6#, fork on queen and knight) 24.Qg3-a3# and the black knight is lost. Of course, the appealing fork on c2 would allow White to capture the black queen before his own king can be captured !
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