The Rd2/ Bd5 battery is white's pride and joy. Best of all, the Rd2 is not on the same rank as the white king, so a black rook capturing on d2 does not give check. This gives white a free move to do something dangerous.

How to pull the trigger? 31. Bf7 appeals straight away because it threatens 32. Qxg6+. Okay, so white offers his Rd2, but he gets an attack in return. Then we need to check the different variations:

31...Qxf7 drops the exchange to 32. Rxd8.

31...Rxd2 32. Qxg6+. The white queen will chase the black king around the Bf7 until Kd6/ Rxf6#. Yum.

31... Kxf7 (the game continuation) 32. Rxd8 Qxd8 33. Qb7+ and the Ra6 drops.

I sometimes think that chess is a bit like a Hollywood pitch. You get a creative type who will "pitch" his idea for a movie to a studio boss. Something like this: "It's gonna be like Die Hard ... on a battleship! We'll get Steven Siegal to be the Bruce Willis character, only he's a navy seal not a cop. Tommy Lee Jones as the baddy. And some token eye candy popping out of a birthday cake."

That's a bit like our initial idea for the combination: "It's Bf7 followed by Qxg6+. With an attack on the Rd8 thrown in for good measure."

Of course, we don't know if the idea is going to work, so after the initial pitch comes the money men. The suits will check every detail to make sure that it's going to make money. Is Siegal available? Can we borrow a battleship from somewhere? How much is it going to cost to make it? What audience figures can we expect? A summer blockbuster or a straight to DVD, made for TV special?

And that's like our analysis mode - checking to make sure that black doesn't have a defence in each variation.

When we play chess, we need to be both the creative types (floppy hair, audis and apple macs) and the suits (short hair, ties and spreadsheets). We need the imagination to spot the tactics and the precision to make sure that they work.

But for some reason, I didn't consider Qb7+! forking K+R to win the exchange via the OTHER rook.

Back on the current day, yay. Just with three points though.

<31.?>

Target: 6:00;000
Taken: 3:19;079

Material: White up, ls♗+♙/ds♗

Candidates: <[Rxf6]>

-ML-
The opposite color Bishops suggest a draw in a potential endgame, but Black neglected his piece activity. The terrible Rook on a6 and the outpost of the Bishop on d5 suggests the relatively simple:

<31.Rxf6> because of 32.Rf7† and 32.Qxg6† Black has no zwichenzug and has to capture.

<31....Kxf6 32.Rd3> such an elegant but effective move. White threatens a new 33.Rf3† Kg7 34.Rf7† and it's very hard to par with.

/A\
<32....Kg7 33.Rf3 Rf8> what else here?

<34.Rxf8 Kxf8 35.Qxg6 > wins.

/B\
<32....Rxd5> nice try but it comes too late.

31 Bf7 expecting Kxf7 32 Rxf6+ Kxf6 33 Qh4+ Kg7 34 Rxd8 with a powerful attack. In this line 33...g5? 34 Qxh6+ will leave White with at worst Q for two disorganised Rooks, or alternatively winning back the Rd8 in more favourable circumstances. Alternatives are 31...Qxf7 32 Rxd8 winning the exchange; or 31...Rxd2 32 Qxg6+ Kf8 33 Qxf6 or Rxf6 with a powerful attack: Rxf6 is playable since the Bf7 is available to cover on d5 (with discovered check) if Black attempts 33 ...Rd1+ 34 Kg2 Qc6+??.
Time to see how the game went:
====
No credit since (A) Stahlberg's fork (on b7) is a much more accurate liqidation after 31...Kxf7 and (B) on playing through the position 32 Rxf6? actually LOSES since after 32...Kxf6 33 Qh4+ g5! WINS since there is a flight square for the Black King on f5. I haven't time tonight to explore fully the lines with Crafty defending, but here is the puzzle position

click for larger view

A) 31... Rxd2 32.Qxg6+ Kf8 (32... Kh8 33.Qxh6#) 33.Qg8+ Ke7 34.Qe8+ Kd6 35.Qe6#.

B) 31... Kxf7 32.Rxd8

B.1) 32... Qxd8 33.Qb7+ Ke6 34.Qxb7 Qd1+ 35.Kg2 + - [R+P vs B].

B.2) 32... Ke7 33.Rf8 Kxf8 (33... b5 34.cxb5 Rb6 35.Qa8 c4 36.Rg8+ Kh7 37.Qe8 wins) 34.Rxf6+ Ke7 (34... Ke8 35.Qxg6+ wins the queen or mates; 34... Kg7 35.Qxg6+ Kh8 36.Rf8#; 34... Kg8 35.Qxg6+ Qg7 36.Qe8+ Kh7 37.Rf7, etc.) 35.Qxg6 with the double threat 36.Qg7+ Kd8 37.Rf8# and 36.Rf7+.

B.3) 32... Kg7 33.Rf8 is similar to B.2 (33... Be7 34.R3f7#).

C) 31... Qxf7 32.Rxd8 Ra7 (32... Bxd8 33.Rxf7+ Kxf7 34.Qb7+) 33.Rd6 with the threat 34.Rfxf6, etc.

D) 31... Bg5 32.Rxd8 Qxd8 (32... Bxd8 33.Qxg6+ Kf8 34.Qg8+ mates in two) 33.Qxg6+

D.1) 33... Kh8 34.Be8 Qe7 35.Rf7 wins.

31. ♗f7 ♖xd2?? 32. ♕xg6+ ♔f8 33. ♕g8+ ♔e7 34. ♕e8+ ♔d6 35. ♕e6+

2) b6 pawn is on an half-open b file and it is sufficiently defended

3) bishop of opposite colour. White bishop sits on a powerful d5 square while f6 bishop is hammered in by the e5 pawn

4) f3 rook controls the f file and attack the f6 bishop

5) a6 rook is out of play and d2 rook is unprotected

6) black kingside lacks second rank pawn protection. It has a weak g6 pawn and f7 and g8 square weaknesses.

candidate: Bf7

31.♗f7!

The threat 32.♕xg6+ is so deadly black must counter it immediately. Unfortunately for black, no matter how he takes the bishop, he loses an exchange.

31...♔xf7

Of course, if 31...♕xf7 32.♖xd8.

32.♖xd8 ♕xd8 33.♕b7+

a) 18 Kxf7 19 Rxd8 Qxd8 20 Qb7+ winning the exchange

b) 18 Qxf7 19 Rxd8 winning the exchange

c) 18 Rxd2 19 Qxg6+ Kf8 20 Qg8+ Ke7 21 Qe8+ Qd6 22 Rxf6#

Stockfish 16 says:

31. Bf7 Kxf7

(31. .. Kxf7 (1. ... Kxf7 2.Rxd8 Qxd8 3.Qb7+ Kf8 4.Qxa6 h5 5.Qb7 g5 6.Qe4 Qd1+ 7.Kg2 Qd6 8.a4 Kg7 9.Rd3 Qe6 10.h3 h4 11.gxh4 gxh4 12.Rd5 Kh6 13.a5 bxa5 14.Rxc5 Qg8+ ) -5.96/37 84)

score for Black -5.96 depth 37.

If I force SF to play my choice it's equal strength:

31. h4

(31. h4 b5 (1. ... b5 2.h5 Kh8 3.Qxg6 Qg7 4.Qe4 bxc4 5.Bxc4 Rxd2 6.Bxa6 Rd6 7.Bc4 Qe7 8.Rb3 Qe8 9.Rd3 Rd4 10.Rxd4 cxd4 11.Bd3 Kg8 12.Qh7+ Kf8 13.Bc4 Bg5 14.Qh8+ Ke7 ) -5.80/41 222)