Friday, 28 October 2016

003. Not the Exchange Variation

White: W. Wittmann - ICCF EU/M/GT/368, 1992

The Ruy Lopez Exchange Variation used to make me cross: 1 e4 e5 2 Nf3 Nc6 3 Bb5 a6 4 Bxc6 – Bleurgh! How can anyone play like this?! At least, that's what I thought back then. Nowadays, I often play “boring” lines myself, such as 1 e4 c5 2 Nf3 d6 3 Bb5+!. Taking an opponent out of their heavily-prepared opening system can be very effective, especially if they're fed up that you have. I lost more than one game to the Exchange Spanish largely through being fed up.

In chess, more often than not, “boring” simply means a position where you don't have any ideas. Whenever there's a variation you don't like, which you decry as “boring”, I think the most sensible course is to study it until you do like it, until you do have some ideas, and in fact there are plenty of interesting lines for Black to choose from after 3...a6 4 Bxc6. One move does not a boring game make. I didn't do that though. Instead, I decided irascibly to circumvent the issue by not playing ...a7-a6 at all. So there.

Around this time, I came across a book in a tournament bookstall bargain bin: Spanish: Schliemann (Jaenisch) by Leonid Shamkovich and Eric Schiller (Batsford 1983). (Which, incidentally, has more typos than any other chess book I've ever seen.) And on page two, there was the following diagram:

I've taken several openings into my repertoire because I liked a particular diagram in a particular book, and this one – showing the basic tabiya of the Schliemann – was really quite appealing to me. White has played the Ruy Lopez, the Variation of Champions, and Black has just pushed the f-pawn at it disdainfully. Pah!

So how does 3...f5 avoid the Exchange exactly? What if White takes on c6 anyway? As with 3...a6 4 Bxc6, the usual recommendation for Black is to recapture with the d-pawn, and in the Schliemann there is the additional trap 4...dxc6 5 Nxe5?! Qd4 6 Qh5+?? g6 7 Nxg6 hxg6 and wins, since the black queen defends the h8-rook backwards along the diagonal. But assuming White doesn't fall for that and plays, say, 5 Nc3 – what then? Nothing much, it seems. White can try and grind that out too, as I have occasionally done myself in thematic tournaments.

That brought me to 4...bxc6!?. Shamkovich & Schiller (most likely the latter) write: “4 ... bc would be pointless here”. I beg to differ. 4...bxc6 has definite points: it gives Black an extra central pawn, the light-squared bishop can sometimes be developed at a6, and most significantly of all – it's not 4...dxc6. After 4...bxc6, the nature of the game is substantially changed, so White can't contentedly and complacently grind. For instance, 5 Nc3 now allows Black a fine centre after 5...fxe4 6 Nxe4 (or 6 Nxe5? Qg5 7 Ng4 d5) 6...d5.

The critical (or at least critical-looking) continuation is 5 Nxe5, winning the e5-pawn and threatening Qh5+ as well. Obviously this can't be answered by 5...Qd4 here (the d7-pawn is in the way); but Black has 5...Qe7! instead, when 6 Qh5+ g6 7 Nxg6 Qxe4+ or 7...hxg6 offers good play; while 6 d4 leads to the current game which, as you'll see, turned out very well for me.

My opponent, Walter Wittmann, an OTB IM, used to play literally hundreds of postal games at a time. You can't conduct as many as that and hope to maintain a consistently high level, but Dr. Wittmann wasn't bothered. He used them purely as a means of researching and testing his OTB openings, picking CC players’ brains as it were. I guess what he learnt from this one is that 4...bxc6 5 Nxe5 Qe7 offers Black good play.

He did later try 4 Bxc6 again – in W.Wittmann-H.Kotz, Austrian League 2001. Whether he'd found a new idea for White after 4...bxc6 was not revealed, since the game continued 4...dxc6 5 Nc3, the line I was aiming to avoid. Okay, Black managed to draw without much trouble, but it certainly didn't look as much fun.

Thursday, 20 October 2016

002. Skirting the Troitsky Line

Black: juliangon - thematic tournament,, 2016

Alexei Alexeyevich Troitsky (1866-1942) was a Russian analyst and study composer. One of his achievements was his definitive investigation of the endgame: king and two knights vs. king and pawn.

As we learn early on, two knights can't force mate against a bare king because stalemate always comes first. But give the defending side a pawn as well and stalemate doesn't apply. In that case it all depends how far the pawn has advanced, whether it can promote before the knights are ready to give checkmate. And how far is far enough depends upon which file the pawn is on. Troitsky worked out that if the pawn is blockaded by a knight no further forward than the fifth rank (RP, QP, KP), fourth rank (BP) and third rank (NP), then the knights have time to mate a cornered king. The imaginary pattern drawn across the board by this theoretical pawn is known as the Troitsky Line.

The tablebases now have five-piece (and six- and seven-piece) endgames worked out to perfection. Nevertheless, they have been unable to improve significantly on Troitsky's original analysis, which, according to John Nunn in Secrets of Minor-Piece Endings (Batsford 1995) was “astonishingly accurate”. Astonishing is the right word. Primarily because, given that one of the knights is stuck on blockading duty, how on earth do you drive the enemy king into a corner with just king and knight? Why doesn't it keep getting away?! Alexei Troitsky, presumably by means of extremely complicated retro-analysis, managed to prove that, while the king does keep getting away, in the final event it finds itself in a situation from which it can't escape.

Well, that was two knights vs. a single pawn. How about three pawns? I reached this ending in a recently finished online game. R+3P vs. 2N+3P eventually became 3P vs. 2N, at which point the Lomonosov endgame tablebases declared mate in 103. Fascinating!

It took me quite some time to understand why I was losing.

In the diagram Black has just played 57...Kf3! (the unique winning move). White can't jettison the a- and c-pawns because the h-pawn is much too far back. In fact doing so sees the white king corralled very quickly: 58 a6 Nxa6 59 c7 Nxc7 60 Kh4 Ne6 61 h3 Ng8 62 Kh5 Ne7 and mate in 10. So the game continued 58 Kh4 Kf4 59 Kh3 Na6! 60 Kg2 Kg4 61 h4 Ne8! (not 61...Kxh4? 62 c7 and draws) 62 h5 Kxh5, and now if 63 c7 then 63...Nexc7! and Black wins because the remaining white pawn is safely blockaded behind the Troitsky Line. The tablebase declares mate in 90.

Okay, we could have played that out, but there seemed little point. We were only continuing at all because the endgame was so unusual. So I found a different way to lose, one involving two little "traps": 73 Ka7!? (the "best" move 73 Kc8 leads to mate in 65), when 73...Kxc6? (or 71...Kxc6?) is stalemate, while 73...Kxa5? is a draw by Troitsky. The way Black solves this problem is quite nice: 73...Ne8! 74 Kb7 Nd6+ with mate in nine.

Saturday, 1 October 2016

001. Playing That Rubbish

White: M. Mossekel - ICCF WT/M/644, 1994

A clubmate of mine, Kevin Simpson, recently played at the Paignton Congress, one of GM Keith Arkell's regularly haunts. On learning that Kev was from Mansfield Chess Club, Keith quipped: “Are they still playing that Wagenbach rubbish?”

The answer to that is: Yes, Keith, we're still playing it — for 25 years now, and it's still not been refuted.

The “rubbish” to which Keith is referring is a defence to the King's Knight Gambit: 1 e4 e5 2 f4 exf4 3 Nf3 h5!?, invented in 1991 by another Mansfield stalwart, János Wagenbach (aka ‘The Master’). Okay, “rubbish” is not unfair comment, given that 3...h5 did start out as a joke... the King's Gambit (itself) is such rubbish that I can even play 3...h5!? against it! Ha ha ha, very funny! — so how come I'm not winning?

And the more we looked at it, the less White seemed to be winning. What really caught my interest was the variation 4 Bc4 h4! 5 d4 g5 6 Ne5 Nh6 7 Qh5 Qf6.

Obviously 8 Nxf7 Nxf7 9 Bxf7+ Qxf7 10 Qxh8 just wins here – so much for that 3...h5 rubbish! – except that it doesn't. Black plays 9...Ke7! instead and White loses a piece. Quite a nice trap.

This scenario has played itself out in 63 games so far, at least up to 7...Qf6, at which point White usually realizes it's not going to be so easy after all and tries 8 Nc3 – as in the following game, my first with the Wagenbach at correspondence chess. (Both János and I had previously played 3...h5 over the board, the first recorded game being D.Newhouse-J.J.Wagenbach, Burnley rapidplay 1992.)

Actually, my response 8...Bb4 wasn't the best. It was later established that Nc3-d5 isn't a serious threat, so Black can simply continue 8...d6!, and if 9 Nd5 then 9...Qd8, or 9 Nf3 Rg8, threatening to trap the queen with ...Bg4. Yes, White can regain the gambit pawn with 9 Nxf7 Nxf7 10 Bxf7+, seeing that 10...Ke7 is no longer possible; but after 10...Kd8! 11 Qg6 Qxg6 12 Bxg6 Nc6 13 Ne2 Bg7 14 c3 Ke7!, followed by ...Kf6, the bishop on g6 is suddenly embarrassed and White loses the pawn once more, this time for no compensation whatsoever.