The bishop-check sac 24.Bxf7+ is just a forcing move you've got to look at, and that's where I started. After 24...Kxf7, I saw that I recovered my piece a pawn better with 25.Rxd7+, noting that Nf6 is pinned.

I expect black to unpin with 25...Kg8. Next, I noticed that white's Q was in attacking range of my knight, and I thought it might continue with some combination that sets up a K+Q knight fork -- if I can get the king to f6. I noticed that I could do just that with 26.Rxg7+! Kxg7 27.Qxf6+ Kxg6 setting up 28.Nd5+, which leaves me with 2 pieces for a rook, which is okay, but not terrific.

I found this one through a process a bit like making a scrap book. Okay, I know that sounds a bit daft, even for me, so I'll explain...

The thing that jumps out of the starting position is that weak black queen. If I could play Nf5+, her majesty would die. But of course 24. Nf5 isn't check - at least not yet - so we'll clip that one out and forget about it for now. I might be able to play it if the black king wanders into the range of my knight.

Then you notice that the black queen is menacing two white pieces - the Bb3 and the Ra1. Hmmm - I'd better do something about that, but not quite sure what. Maybe I need to move one or both of those pieces?

Then the weakness of f7 becomes apparent, with both the Bb3 and the Qf3 staring at it. We notice that the Nf6 is pinned against f7 by the queen. Not quite sure what to do with this information, so I'll clip it out and use it later.

24. Rxd7 seems interesting, because 24...Nxd7 allows 25. Qxf7+. But then it seems to fizzle out. Cut it out and keep it for later.

All the time we are looking at different variations, we are collecting snippets of information about the position. So far we have the possibility of a discovered attack on the Qc3, the weakness of f7 with a potential pin on the Nf6, the move Rxd7 and the need to do something about the black queen's attack on Bb3 and Ra1.

That's the bit that's like a scrap-book - collecting odd things in case they might be useful later. Then we have to rearrange them into a sensible order. It's only when you start to combine some of these elements that the tactic becomes clear:

24. Bxf7+ (moves one of the threatened pieces and draws the king onto the juicy f7 square to pin the Nf6). 24...Kxf7

25. Rxd7+ (one of our remembered moves, which exploits the fact that the Nf6 is now pinned) 25...Kg8.

26. Rxg8+ (not one of the moves we visualised from that start, but tempting because g7 is within range of Nf5). And the rest is easy. We finally get to play the Nf5+ that we first thought of, or Qxf6 if the black king tries to wriggle away.

Analysis by Rybka 3 1-cpu: depth 17 time 3 min 15

1. (2.66): 24.Bxf7+ Kh8 25.Bd2 Qc7 26.Bxg6 Re6 27.Nf5 Nf8 28.Rac1 Rc6 29.Bxh6 Bxh6 30.Nxh6 Rxc1 31.Qxf6+[] Qg7 32.Nf7+ Kg8[] 33.Qxg7+ Kxg7 34.Rxc1 Nxg6 35.Nd6 b5 36.axb5 axb5 37.Nxb5 Nf4 38.Kf1 Ra2 39.Nc3

click for larger view

Two candidate moves: (A) Bxf7+ and (B) Rxd7. Dealing with (B) Black defences include Qxa1 with powerful threats. It is too late (23:42 21/01/2010) to go further tonight, it will still be there in the morning.

Getting back to Friday here :).

Target: 3:30;000
Taken: 2:30;982

Material: Black up, ++ / 2

Candidates: Bb2, Rxd7, <[Bxf7†]>

-ML-
I was looking at ways to trap the Queen but it stops quickly after it's obvious Bb2 cannot be played. So, the attention goes to the Black King and the weak Knights. Knights defending each other CAN be a nice asset but usually, especially in open positions, it's a liability because they cannot move if both attacked. White abuses it differently here, but it shows they aren't well placed. I saw the key soon enough, which is:

<24.Bxf7† Kxf7 25.Rxd7†> it's difficult to spot what a follow-up can be. I noticed one nice follow-up which is impossible. I'm, for once, not gonna work from worst to best, just what I spot first (it might be better for all else too actually).

/A\
<25....Re7> loses by force, although not so obvious:

<26.Rxe7† Kxe7 27.Qxf6†!! > on any capture White has the same fork with Nd5†, winning the Queen back with a Knight profit. Clear enough. Okay, next.... Kg8 seems bad due to the same threat:

/B\
<25....Kg8 26.Rxg7†! Kxg7 27.Nf5† > and it is. As much, Kf8 loses in the same way.

/C\
<25....Kf8 26.Rxg7 > as the pressure is too big now. That leaves the suicidal looking Ke6.

/D\
<25....Ke6> although it puts Bg7 en prise, so are both of the White Rooks. However, it's the stronger piece that's still the problem for Black.