It seems likely to me that somewhere in this combination, white will allow black to capture the bishop on c1 with check and simply move the king (after all, this bishop will not help us in the near future). The black queen will be on such a poor square for the defence of her king that the piece and move simply won't matter to white's plans.

This all comes about because it appears that black has woefully neglected the development of his king side pieces so that his queen may go gallivanting around the board capturing white's rook(s).

The real question here is, "Do we start with a forcing move (eg 22 Bc6+) or is this the moment we give black the bishop and move by playing something subtle, such as 22 Qc4.

We should start by making a list of candidate moves. I see...

22 Qc2 (just because, but I'm sure this isn't it)
22 Kh2 (also unlikely)
22 Bc6+
22 Qc4
22 Qd5
22 Bd5
22 Bxg6+
22 Nd6+
22 Qf3
22 Nc7+

There are other "forcing moves" (such as 22 Qd7+), but they seem very unlikely to me.

OK, the more I look the more I like

22 Qd5

as the key move. This attacks the black knight, which cannot move (22...Nf4 23 Nc7#). I expect black to try and scoop up the bishop with

22...Qxc1+ 23 Kh2

and now what? Trying to save the knight is futile (23...Kf7 24 Nc7).

Taking the pawn with 23...Qxb2 doesn't work for black as after 24 Qxe6 Qxb5 25 Bc6+ wins the queen.

And 23...Qe1 is no better after 24 Qxe6 Qxe4 25 Nd6+ Kd8 26 Qc8#.

I think this is probably it, time to check.

=====

But first a true story, if I may. Around a decade ago, the Mem and I were singular people both recovering from messy divorces. And as friendship deepened to affection, and affection grew to be love, we started talking about marriage. It was a scary topic for two people who had tried it <once> and not enjoyed it at all. Whichever idiot said "it is better to have loved and lost than never to have loved at all" clearly hadn't met our respective exes.

And there came a day when the Mem asked: "What is marriage anyway? Is it just another cage to stop you from living as you want?"

Hmm - deep stuff, and a tricky question for a would-be husband to answer. It's a bit like the "does my butt look big in this?" question, where you feel that anything you say will be wrong.

So we drank some more wine, laughed a lot and the talk flowed and played around the answer like the tide eddying around a rock. And eventually we decided that marriage could be a cage, but only if you made it so. It could also be a rock, a solid foundation for life, to give you the security you need to be free. A cage with an open door is a home.

Today's puzzle features several caged pieces. The white Bc1 has zero moves, at least until the b and d pawns get out of the way. The black Bf8 and Rh8 are not quite so trapped, but they are still several moves away from liberty. a1 seems an odd square for the black queen. Black is a long way from castling his king to safety.

But what to do? Protecting the Bc1 with 22. Qc2 seems like a grubby little defensive move when we are the exchange down and black is so behind in development. Let's leave that piece to its fate (even if it comes with check) and look for an attack.

22. Bxg6+ hxg6 23. Qxg6+ appeals because of its forcing nature, but I can't see a decent followup. Discard.

And then we notice the black knight sitting undefended on e6. It may be in the middle of the board, but it is trapped inside a virtual cage with very few escape squares. And that's when we find 22. Qd5 which seals the cage door shut. Now if the knight moves we play 23. Nc7#. If the king moves to protect the knight with 22...Kf7 we play 23. Nc7 with a crushing attack.

But there's a twist to the tale, and I must confess that I missed it in my initial human mode analysis. After 22. Qd5 Qxc1+ 23. Kh2 Bh6 we get to here:

click for larger view

There is a cunning little trap waiting for white if he is careless. You might think (as I did at first) to grab the knight with 24. Qxe6. But that would throw away the advantage in a heartbeat. Black would play 24...Qxd2, which defends against the white mates and threatens an attack by black against the white king.

Instead, 24. Nd6+ keeps the black queen inside its back rank cage. And the rest you can see for yourself. The white bishop and queen weave a mating net around the black king.

The final position contains a hint of humour. Black can try to run his king to safety, but the net just swivels through 90 degrees and catches him anyway: 28... Kc7 29. Qd7+ Kb6 30. Qb7+ Ka5 31. Qa6# (or 31. Qb5#)

Black could play better 21...Bg7 (with idea 22...Kf8) and it was not so easy to win for White, even with a better position.

But even after 22.Qd5! Black could resist more with 22...Qa6 (23...Qxc1+?? loses immediately) 23. Qxe5 Bg7 24. Qxg7 Nxg7 25. Nc7+ Kd7 26. Nxa6 Kd6 27. d4 cxd4 28. cxd e5

White's game is clearly won, but it takes at least 20 moves more to win the endgame 2 Bishops + 1 pawn vs. 1 Rook.

However, Black could avoid to enter this kind of positions, by playing 11...Ne5 followed by 12...Bg7

White has sacrified the exchange for, at first sight, very little. But he has the shot 22 Qd5!? and now
(A1) 22...Qxc1+ 23 Kh2 Nf4?? 24 Nc7# (A2) 22...Nf4 23 Nc7#; (B1) 22...Qxc1+ 23 Kh2 Kf7 24 Nc7 winning back a B with mating threats coming on f7; (B2) 22...Kf7 23 Nc7 and Black cannot usefully use the Q to protect the Ne3 so must transpose back to B1;
(C1) 22...Qxc1+ 23 Kh2 Bh3 24 Qxe6

The only sensible alternative to 22 Qd5 is 22 Qc2 which allowing Black to unravel with Nf4: if 22 Qc2 Nf4 23 d3 (or Na3) Qxc1+! winning on material

Time to check:
====
I got some of it.

Time to see how I get on against Crafty End Game trainer starting from the puzzle position:

click for larger view

http://www.chessvideos.tv/endgame-t...

The answer is not very well: I cannot get more than perpetual check. Over to the other kibitzes to see if the win is there.

POSTSCRIPT: Could Black have forced a draw? After 22 Qd5 Crafty EGT defends with 22...Bg7!. The best I can find for White is 23.Nd6+ exd6 24.Qxe6+ Kd8 25.Qxd6+ Kc8 26.Qxc5+ Kd8 27.Qb6+ Ke7 28.Qb4+ (White has too little material to mate, so hopes for an ending with PPP for the exchange) Ke6 29.Qb3+ Kf6 30.Qc2 Bh6 31.Kh2 (not 31 Qb1? Qxb1 32. Bxb1 Ra8! and scoops a Bishop) Qa7 32.d4 Bxc1 33.Qxc1 exd4 34.Qf4+ Ke6 35.cxd4 Qxd4 36.Bf5+ Kd5 37.Be6+ Kc5

click for larger view

and now neither 38.Qc7+ nor 38.b4+ quite win, whilst the ending after 38 Qxd4+ is presumably drawn.

This bold move prepares to make a sham sacrifice of two White pieces for decisive mate threats against the helpless Black King position.

Here's a breakout with Fritz 10:

< 22. Qd5!!> This bold move, preparing to give up two pieces for decisive mate threats, was made possible by Black's speculative 21...Qa1?! Instead, 21...Bh6 would have put up more resistance.

<22...Qxc1+>

If 22... Kf7, then White mates after 23. Nc7 Qxc1+ 24. Kh2 Qxb2 25. Qxe6+ Kg7 26. Ne8+ Kh6 27. Qg4 g5 28. Bf3 Qxd2 (28... Kg6 29. Qe6#) 29. Qh5#.

<23. Kh2 Bh6>

If 23... Qxb2 24. Qxe6 Qxb5 25. Bc6+ Qxc6 26. Qxc6+ White wins the Queen and the game.

<24. Nd6+!> Perhaps this is the move Black overlooked when he played the greedy 21...Qa1?!

<24...exd6>

If 24...Kf8, then White puts Black back into the mating web with 25. Qxe6 Bf4+ 26. g3 Bxg3+ 27. Kg2 .

If 24... Kd7, then it's a quick mate in two 25. Qc6+ Kd8 26. Nf7#.

<25. Qxe6+ Kd8>

No better for Black is 25... Kf8 26. Qf6+ Ke8 27. Bc6#.

<26. Bc6 Bf4+ 27. g3 Bxg3+ 28. Kg2 1-0>

The first question is whether white can afford to play any other move without playing Kh2 first. So I tried 22 Kh2. It turns out black has an out with 22…Nf4!, below, forcing white off of the d file, so 22 Kh2 is no good.

click for larger view

Then I saw that if 22 Qd5 first, then 22..Nf4?? is disastrous (It leads to mate in one with 23 Nc7#, as <dzechiel> stated).

Then I observed that 22 Qd5 Qxc1+ 23 Kh2, below, leaves black very vulnerable.

click for larger view

Black’s knight is pinned as white still has the mate threat Nc7. In addition, black’s queen is buried behind white’s pawns. <dzechiel> first posted the solution with this variation.

So, the question left is what happens after 22 Qd5 Bg7? After the forcing moves 23 Nd6+ exd6 24 Qxe6+ Kd8, how about 25 Bc6!?, threatening mate in one?

click for larger view

Now, if 25…Qa7, 26 Qxd6+ Kc8 27 d3 follows, letting the bishop back into the game.

click for larger view

(I) 22.Bg6+?? hxg6 23.Qxg6+ Kd7 leaves white with insufficient attacking force and no useful continuation.

(II) 22.Nc7+?? Nxc7 23.Bc6+ Kf7 24.Qf3+ Ke6 is similar.

(III) 22.Nd6+?? exd6 23.Qb5+ Kf7 24.Qb7+ Be7 goes nowhere.

(IV) 23.Bc6+?? Kf7 24.Qf3+ Nf4 25.g3 (Be5+ e6) Qxc1+ 26.Kh2 Qxd2 and black has more than adequate defensive resources.

The primary lesson from examining the above forcing moves is that white must preserve both active minor pieces to maintain a credible attack. The secondary lesson is that the Ne6 can be an plucky defender, but it sits on a very weak square. After about a half-hour consideration, I finally found the candidate I liked.

22.Qd5!!

Attacking *and* paralyzing the knight. White threatens 23.Qxe6 followed by 24.Nd6+ forcing mate. The move also controls a2 and d2, making it hard for the BQ to get back for defense. Black's defensive options are limited:

A) 22... N moves?? 23.Nc7#

B) 22... Qxc1+ 23.Kh2 Qxb2 24.Qxe6 Qxb5 (otherwise 25.Nd6+ etc) 25.Bc6+ Qxc6 26.Qxc6+ (Qd5+ may be even stronger) Kf7 27.Qxc5 and the white c-pawn looks like a winner.

B.1) 23... Kf7 24.Nc7 Kg7 25.Qxe5+ Kh6 (Kg8 26.Qxe6+) 26.Nxe6 Qxd2 (otherwise 27.Qg5#) 27.Qxh8 wins.

B.1.a) 24... Bg7 25.Qxe6+ Kf8 26.Bd5 forces mate.

B.1.b) 24... Bh6 25.Qxe6+ Kg7 (Kf8 26.Bd5) 26.Qxe5+ Kg8 27 Bd5+ wins.

B.1.c) 24... Kf6 25.Qxe6+ Kg5/g7 26.Qxe5+ wins.

B.1.d) 24... Rg8 25.Qxe6+ Kg7 26.Bd5! Rh8 27.Qxe5+ wins.

B.2 24... Bh6 25.Nd6+ Kd8 (Kf8 26.Qf7#) 26.Qc8#

C) 22... Qa5 23.Qxe6 Qxb5 24.Bc6+ wins.

D) 22... Qa6 23.Bd3! (Qxe5? Bg7 helps black) Kf7 (Nf4? 24.Nc7#!) 24.Bc4 Qb6 25.d4! cd 26.cd ed 27.Nxd4 wins

D.1) 23... Bg7 (or h6) 24.Bc4 Kf7 25.Nc7 wins.

D.2) 24... Kf6 25.d4! cd 26.cd ed (Nxd4 27.Qf7#) 27.Nxd4! Nxd4 (Qxd4 28.Qxe6+) 28.Bg5+ Kg7 29.Qf7#

click for larger view

Now 34...Rd3 loses to Qb3+ Kc8 Qg8+ winning the exchange then the Bg7, so 34...Rd1+ 35.Kh2 e4+ 36.g3 Qb6 (transposing by force to a lost ending, but alternatives are worse) 37.Bd6+ Rxd6 38.Qxd6+ Qc7 39.Qxc7+ Kxc7 40.Bxe4 Kd6 41.f4 Kc5 42.Bd3 Kd5 43.Kg2 Bf6 44.Kf3 Ke6 45.Ke4 h6 46.h4 winning easily three pawns up despite the Bishops of opposite colours.

2) c1 bishop is pinned and it is shut out by the b2 and d2 pawn. White should leave it to its' doom because Qxc1+ put the queen out of place defensively

3) Black has a bad bishop hammpered in by the e7 and e5 pawns. However, it threatens to finish kingside development with either Bg7 or Bh6

4) Black knight did an amazing job holding everything together. It stops Nc7+, it blocks Qf3 with Nf4 and it shields the weak a2-g8 diagonal. White should play to get rid of this strong defensive knight

5) If White should have any chance of success, he should also include his knight as part of the attack. The knight controls weak dark squares in Black's camp.

Candidate: 22 Qd5

Passive defence: a) 22...Qxc1+ 23 Kh2 Kf7?! 24 Nc7! Bh6 25 Qxe6+ Kf8 26 Bd5 Bf4+ 27 g3 Bxg3+ 28 Kg2! Kg7 29 Qxe7+ Kh6 30 Ne6! Bf4 31 Qh4#

active counterplay: b) 22...Qxc1+ 23 Kh2 Bh6 24 Nd6+!! (if 24 Qxe6? Qxd2! 25 Nc7+ Kd8 - Black' threatens 26 Bf4+ 27 g3 Qxf2+ mating while white's attack comes to a stop) 24...exd6 (if 24...Kd8 25 Qa8+ Kc7 26 Qc6+ Kd8 27 Qc8# and if 24...Kf8 25 Qxe6 Bf4+ 26 g3 Bxg3+ 27 Kg2 dxe6 28 Qf6+ Ke8 (or 28...Kg8 29 Bd5#) 29 Bc6#) 25 Qxe6+ Kd8 26 Bc6! Bf4+ 27 g3 Bxg3 28 Kg2! Kc7 29 Qd7+ Kb6 30 Qb7+ Ka5 31 Qb5#

22.Qd5 Bg7 23.Nd6+! (In my first attempt, I erred with 23.Qxe6, producing the draw described by David.) exd6 24.Qe6+ Kd8 25.Qxd6+

A perfectly sound alternative to the move 25.Bc6 suggested by <JimfromProvidence>. The idea is to bring the bishop in with check if the BK moves to a light square.

25... Kc8 26.Qxc5+ Kd8 27.Qb6+ Ke7 28.Qc5+ Kf6 29.Qd6+ Kg5 30.Qe7+ Bf6

click for larger view

31.f4+! (h4+ is weaker!) Kh6 32.Qxf6 Qxe1+ 33.Kh2 Qxd2 34.Qg5+! Kg7 35.Qxe5+ Kh6 36.Qxh8 Qxf4+ 37.Kg1 Qe3+ 38.Kf1 Qxe4 39.Qf8+ Kg5 40.Qd8+ Kf5 41.Qd7+ Kf6. 42.Qd4+ forced a won K&P ending.

Black depth 17 : 3 min :
(+3.79):21...Qa1.took the Queen out of play.
Best. Bh6, +0.59, Bg7, 0.72.

Black depth 27 : time 1 hour 39 min :
(+6.78):22...Qxc1.wins a piece but allows White's forces to close in for the kill. Best. Qa6, +3.79.

I think there's a faster way for White to win, after 22 Qd5 and 22...Bg7, as suggested by Crafty (and instead of 23.Nd6+ without entering an endgame)

23. Qxe6 Qxc1+ 24. Kh2 Qxd2 25. Nc7+ and now a) 25...Kd8 26. Nd5 Re8 (26...Bf6 27. b4! cxb4 28. cxb4 Qxf2 29. Bf3 [idea Bg4] h5 30. Nb6! and then mates) 27. Bf3 h5 28. b4! cxb4 29. cxb4 Qxf2 30. Nb6! and again White mates.

You are in error, because White can win even faster than I suggested, after 27. f4! and now:

a) 27...exf 28. Nxf6 gxf6 (28...Qf2 29. Bf3 etc.) 29. Qxf6+ Kg8 30. c4! and then mates Bd5 b) 27...Kg7 28. fxe5 Bh4 (28...Bg5 is even worse) 29. Qg4 Qf2 30.Nf4! and White wins

Anyway, why are JUST posting whenever I'm posting, Sastre? It seems that in the last times you are just interested in following me whenever I am posting.