Frankly white is already comfortable with a 2P lead, and would love to trade off pieces.

Trading our Q for a R+N with 26.Qxc8+ Nxc8 27.Rxc7+ Kh7 wouldn't be advisable by itself. However, seeing that our N is in a great forking position, we should find the clever decoy: 28.Rh8+! (decoy) Kxh8 29.Nxf7+ (a bonus pawn) with 30.Nxd6 next.

27...♔h7 28 ♖h8+ ♔xh8 29 ♘xf7+ and 30 ♘xd6. White is then a knight and three pawns ahead. 27...♕f8! 28 ♖xf8+ ♔xf8 and white ends a knight and two pawns ahead.

It is of course easier to spot the combination once one knows it exists. And when one is trying to solve a puzzle, one is aware that there must be a solution.

Nonetheless there is another way to know there is a solution without being 100% sure there is actually one. When you' re playing an actual game, you should be aware of some cues that might suggest the presence of tactics. What helps in an actual game and also compensates partly for NOT being 100% sure of the presence of a forced sequence of moves (which one might call 'tactic') is the fact that one has been commited since the very beginning of that game. This 'being-acquainted-with-the-spirit-of-the-game-fac- tor' should help you expecting that there could be a forced sequence of move, if not immediatly, maybe a bit later. Take the position after 23.Ne5 from today' s game, for instance:

click for larger view

It is probably certain that White has been aware of the vulnerability of the black King since a certain time. And so has been Black, as he plays 23. ...Na7 in order to add some protection to the c8-square. But by doing so, Black also removed the queen' s only defender. There is a principle that suggests that almost any forced sequence of moves involves an undefended (or insuffently guarded) piece. Note that I did not write 'almost any position involving an undefended piece brings a forced sequence of move', but rather 'almost any forced sequence of moves involves an undefended piece'.

But why is the black King supposedly vulnerable ? Notice that I used the word 'vulnerable', instead of lost, being given that at this very moment, the black Rook is doing well in protecting the King from back rank mate. For this reason, White, being aware that the black King is not 'matable' right now, has just brought his Knight to e5, first to activate it in the center, but also, to target one of the squares that will allow to attack the undefended black Queen. Should the white Knight reaches f7, it would attack the black Queen AND some squares aroung the King.

See what we mean by 'being-acquainted-with-the-spirit-of-the-position- -factor'? There is nothing absolute, here, only some factors that could somehow make a forced sequence of moves envisionnable. When the white Knight comes to e5, it is centralised AND ties the black Rook down to the protection of f7. When a certain piece becomes overloaded, that is, when it has too many tasks, this increases the probability of a tactic. Here, the Rook defends the King against back rank mate AND defends the vulnerable f7-square. Meanwhile, before playing the Knight to e5, White had to find out that ...f6 offered Qa2+, as now the black King would have to go to the the awkward h8-square. It is now that White notices the key-relation between d6, f7 and h8. When the King goes to h8, it is subject to be forked with it' s Queen by a nasty Knight at f7.

Then comes 24.a4, because White dreams of bringing the Queen to c3 without being bothered by an annoying ...Nb5. And 24. ...h6 becomes almost necessary, as to bring air to the King. The advance of the pawn provides the black King an exit, but only to h7, as g6 is covered by the white Knight. The well advised white player knows that with the black King to h7, a white Rook to h8 AND a white Knight at e5, the Black King would be forced back to the last rank. By the way, 24. ...h5 would not be more efficient here, as a white Knight at f7 covers h6 as well.

By playing 25.Qc3, White adds up some pressure on c8. The Queen also targets g7 AND c7. This very last point threatens to take control of the entire 7TH rank, attacking f7 an other time through 26.Qc7 Qxc7 27.Rxc7, with tempi. This is probably what caused Black' s mistake here.

And when the unfortunate 25. ...Rc8 comes, all White has to do is counting the points. That is because while the game was in progress, he had had the chance to notice that a certain number of factors was evolving. He had become acquainted with the spirit of the game, which ultimately helped him at what chess players call 'pattern recognition'.

I hope this may help. :0)

Peace !

You are certainly getting good value for your question! Here's my three pennorth about how to spot when a combination might be "on".

First, combinations generally occur when you have some form of advantage or your opponent has a disadvantage. It's a bit like Spiderman's spidey sense. You just get the feeling that the position is "juicy" and ripe for tactics. Then it is worth investing some time to look for spectacular moves.

In the starting position for today's puzzle, white has two plusses. He has a queen and rook battery (ie standing on the same open file) and he has a far advanced knight. When knights get to the fourth, fifth or sixth ranks then exciting things often happen.

Secondly, you should always be looking for the contrarian move. The natural instinct for most beginners is to move the queen away when she is attacked. Instead, take a few moments to see what happens if you don't react in the stereotypical way. Can you counter-attack or ignore the threat to your queen?

One way to develop these sorts of instincts is to work backwards from the puzzle position. Once you have found out the winning line, look at the position again to find the factors which make the combination possible, such as rook/ queen batteries and far advanced knights.

You know the Anthropic Principle in physics? At its simplest, it answers the question "why do we live in a universe that seems almost designed for us to evolve and survive in?" -- gravity and other forces with just the right strength, lightspeed neither too hot nor too cold: spooky.

The Anthropic Principle - which some say is just a tautology - asserts that we live in a fine-tuned baby-bear universe because, well, because we do. If it was different there wouldn't be any us around to observe it.

Combinations like this remind me of the Anthropic Principle. It actually hinges on a fact that never comes directly into play: the knight's control of g6. But if g6 wasn't covered then the sac Rh8+ would fail, as the king could run to g6.

So the combination seems designed. Or does it work because, well, that's the way these things work ... and if they didn't we'd have to find another combo.

http://en.wikipedia.org/wiki/Anthro...

and please scroll down to 'Criticisms'.

I quote from the above wikipedia article

"Steven Jay Gould [53] [54], Michael Shermer[55] and others claim that the Anthropic Principle seems to reverse known causes and effects. Gould compared the claim that the universe is fine-tuned for the benefit of our kind of life to saying that sausages were made long and narrow so that they could fit into modern hotdog buns, or saying that ships had been invented to house barnacles. These critics cite the vast physical, fossil, genetic, and other biological evidence consistent with life having been fine-tuned through natural selection to adapt to the physical and geophysical environment in which life exists. Life appears to have adapted to physics, and not vice versa.

Lee Smolin argues using his fecund universes theory that fine-tuning for black hole creation is the fundamental cause for the observed values of physical constants. Conditions for carbon based life are similar to conditions for black hole creation which creates the illusion of the anthropic principle. Instead there is a black hole principle. Compare correlation is not causation."

It's best to present both sides of the argument I think. :)

Profound. Next week: discovered check and string theory ... how Nimzo restrains the branes ...>

<Vaselin Toplove> -- <It's best to present both sides of the argument>

I agree. It *is* best, especially when you're actually making an argument. But I wasn't making one - I think the A.P. idea is interesting, but I'm agnostic on it - I don't care much either way, and I certainly wasn't trying to defend its validity.

I *did* say that some people regard it as a tautology, which at least suggests that there are two (or more) sides. And all I meant was that this game reminded me of it.

And I *really* don't trust Wikipedia, btw, except as a guide to better sources. Almost every time I look up something I actually know about, I find either mistakes or one-sided arguments. I admit I use it a lot, but never as a proof of anything.

If I said that, let's say, Kramnik's play reminded me of minimalist painting, Suttles used to play like a surrealist, and Topalov made me think of eclectic postmodernism, would you want me to give a full description of contemporary art, along with my own opinion? Probably not, but it would be only fair to explain what I meant by the comparison.

Something like this. Kramnik reminds me of minimalism because his style is no style - he has few personal flourishes. He can be highly efficient, or a bit dull - but you'd rarely call his play beautiful. Topalov, on the other hand, is the wildly emotional type of postmodernism, more expressionist, full of energy and personality, but sometimes badly flawed - which is the price you pay for riotous brilliance.

And Suttles was like the surrealists because he seemed to *dream* his games, not play them.

As you might guess, I write about art more than I write about physics. But I'm interested in both, and in links between them and chess.

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