Tuesday, October 30, 2007

October TNT Round 4

Mundwiler - Liu 1-0

Liu, with 15...Ne4, forced Les into a winning combination that culminates in 20.Nd5 (classic theme usually seen in Sicilians.) Incidentally 25. Qd7 would have also resulted in white's King also walking to g6. The way Les played it, the King gets there one move earlier.

Czypinski -Oberton DRAW

The opening was quite quiet but 24...f4 leaves a weak backward e pawn

But play continued 25. Ne4 Nxe4 26. Rxe4 Bf5 and Black keeps the material balance; a drawn Rook and Pawn endgame resulted.
However, after 25. Nf1, the epawn will fall without much fuss.

Silva - Kong DRAW

A very interesting endgame arose after 50. Kxd2

Upon first glance, 50...Kc4 looks natural. 51. Kc2 is forced. Then 51...a5 52. b3+ Kc5, I think White is lost. Black has two main themes: a5-a4 which creates a hole at c4; and the fact that he can create a passed pawn, likely the e-pawn. Take a look, it is great study material, post a message if you have any thoughts.

Kong played 50...f5 which is a little hasty...the availability of having moves like f6 and f5 in reserve can make the difference in endings like this.

Later, this position occurred--White to move.

Silva played 57. f4 ! (although he should have played it on his 56th move)

So the following position arose after 62...Kxa3

Almost anything wins here, including bringing the king over to the queenside and mating, but most of us would pick off some pawns first. Disregarding the quick mating variations, the only thing to prevent is the advancement of the a pawn; the kingside pawns aren't going anywhere.

In the game, 68. Qd4(which was not played) is instructive as it is an easy way to stop the a pawn.

I believe the last chance for White to win was after 72...f3+

73. Ke3 ! Kb1 74. Qb3+ Ka1 75. Qc2 ! the point as there is no stalemate ...f2 76. Qc1 mate.

It was a long game, so time trouble was probably a factor.

Greenberg - Khedkar 0-1

I think it was Jack Woodbury who cautioned me about playing Bf4 "on top" of a fianchetto. Now I am passing that wisdom on to Harley.

Wierda - Aaron Green 1-0

Wierda gives Aaron a knight on move 7, but by move 20 he has 3 pawns for it. Aaron could have regained his advantage with 21...Qxc4, or 28...Qxa5 but did not and lost on move 30.

Rutter - Atem 0-1

Blair made a strategic error by playing 21. bxc4 instead of Rxc4. The open B file immediately gave black tons of obvious play. Well played by James.

Jim Green - Saul Magnusson 1-0

White had a small edge until black hung an exchange in the middle of the board.


Nigel Hanrahan said...

Thanks for the remarks about the Silva-Kong endgame, Tony. The win for White with 73. Ke3! is very amusing as Black seems to have pushed the White king to the f-file where the draw is the expected result. More about that later.

In these sorts of endings with rook pawns, the winning side can sometimes allow the promotion of the pawn anyway. Here's an example from this game: Following 70 ... Kb2, White had the option of playing 71. Kd2! Then we have 71... a1Q 72. Qb4+ Ka2 and now 73. Kc2!! Black's Queen is useless and cannot stop the mate. Similarly, with 72. Qc4+ (instead of 72. Qa3) we have 72... Kb1 73. Kd2 a1Q 74. Qc2#. Underpromoting to a knight will not save Black in this position.

I looked up these sorts of endings in Practical Chess Endings by Paul Keres and discovered that the general rule is that with only one pawn for Black on a2 the White king must be inside the box whose boundary includes d5 and e4 (but not e5). Of course the queen must not be blocked from giving check and preventing the pawn promotion.

Here is an example. With the White king on e4, Queen on g8, Black king on b2 and Black pawn on a2 we have the following: 1. Qg2+ Kb1 2. Kd3! a1Q 3. Qc2#. Again, if Black underpromotes to a knight, then White simply plays 3. Kc3 and mate cannot be stopped.

Here is another example. With the White king on e2, Queen on a3, Black king on b1 and Black pawn on a2 we have the following: 1. Qb3+ Ka1 2. Qc3+ Kb1 3. Kd2 ... after which Black is forced to promote the pawn against an inevitable mate. With the White king on f2, (as in the Silva-Kong game after 74... Kb1) this mate cannot be achieved and the position is a draw.

This all leads to the interesting conclusion that 67 Qxf4 is a better move than 67. Qxe4.

What an instructive endgame! I have to feel bad for Romeo who likely was in time trouble. Congratulations to Dezheng for fighting on in a virtually hopeless position. The spirit of Mike Shpan is alive and well!

Chess Manitoba said...

I first looked at these types of endings back in 1972 or so, when Basic Chess Endings by Reuben Fine was the bible.

I would say that there is no real difference between between 67. Qxf4 and Qxe4 as White still has an easy win by placing his Q on e5 or d4 next move.

I am sure we will get some more interesting endings to look at, the simpler the better.