1 Qg8#

1 Qxh6+ Qh7 2 Qxf6+ Qg7 3 Qxg7#

The obvious defense fails as we have no way to sacrifice the black queen!

39 ... Qc7+
40 g3 Rd2+
41 Kh3 Rxg3?
42 Rxg3

The next obvious defense seems to fail

39 ... Qf8?
40 e7! ...

But what happens if we combine the two!!!?

<39 ... Qf8>
<40 e7 Qb8+!>

Now we have a route for the queen to give check and keep tempo on the white king!

<41 g3 Rd2+>
<42 Kh3 Rh2+!>
<43 Kxh2 Ra2+>
<44 Kh3+ Rh2+!>
<45 Kxh2 Qb2+!>
<46 Kh3/Kh1/Kg1 Qh2+/Qh2+/Qg2+>

click for larger view

<47 Kxh27/Kxh2/Kxg2 STALEMATE>

A nice swindle!

I wonder how many smeegal references we are going to see...

~~~

WHAT!??????

I can't see the draw with Qc7+ as per the annotation, but I can see it with the main continuation which was a loss???!!!!

The black king is in stalemate, if we take the 2R and Q off the board, so all we have to do is "take the 2R and Q off the board", this sort of problem is "quite a normal one" for chess puzzles...

It wasn't too hard to find the main idea. We are close to being mated so we need to find something that defends against the mate threat or gives a mate of our own.

Defending against the mate seems impossible. We can't hold both h6 and f6. 39...Qf8 allows 40. e7.

So we are looking for either a mating attack of our own or a stalemate. And either way that means prising the white king out into the open. I tried Rh3+ and Qd6+ before hitting on Qc7+.

Not too hard for a Saturday.

With

41. ... Qxg3+ 42. Qxg3 Rxg3 43. e8=Q+
or 41. ... Rxg3 42. e8=Q+ Qxe8 43. Qxe8+

followed by 43. ... Rg8 , one gets the position

click for larger view

e.g. Ra8 prevents Qg8 and the Qxh6+ - Qf8+ - Qxg8# sequence, but leaves that leaves white with Qxh6+ - Qxf6 - Qxg7#

So that means we have to try to look for more aggressive solutions.

39...Qc7+ only solution to the problems I see.

a) 40.Kg1 Rd1+ here white gets mated 41.Kf2 Rd2+ 42.Ke1 Qe5+ 43.Kxd2 Qb2+ 44.Kc1 Ra1# b) 40.Rg3 Qxg3+
c) 40.g3 now this is getting tricky
c1)40...Qxg3+ 41.Rxg3 Rxg3+ 42.Qxg3
c2)40...Rxg3 41.Rxg3 Rh2+ is also not working
c3)40...Rh2+ 41.Kxh2 Ra2+ now.
c3a) 42.Kh3 Rh2+ 43.Kxh2 Qxg3+ 44.Kh1 Qg2+ stalemate c3b) 42.Kh1 Rh2+ 43.Kg1 (Kxh2 transposes into the line above) 43...Qxg3+! 44.Rxg3 Rg2 45.Kf1 Rf2+ gotta love the crazy rook motif.

40. Kh1?? Ra1/Rd1#

40. Kg1? Rd1+ 41. Kf2 Ra2+ 42. Ke3 (42. Kf3 Ra3+ 43. Ke2 Qe5+ 44. Kxd1 Qa1+ ) Qe5+ 43. Re4 (43. Kf3 Rd3#) Qc3+ 44. Kf4 Rf1+ 45. Kg4 Qf3+ 46. Kh4 Rh1#

White threatens 40.Qg8# and 40.Qxh6+ and mate in two.

Black can try to achieve either perpetual or stalemate (the passive defense 39... Qf8 loses to 40.e7).

One possibility is to get rid of the queen and rook with 39... Qd6+ 40.cxd6 Rh3+ 41.Kxh3 Rd3+ 42.Rg3 Rxg3+ but after 43.Qxg3 Black is lost.

This suggests 39... Qc7+ instead (39... Rh3+ 40.Kxh3 Rd3+ 41.g3 + -):

A) 40.Rg3 Qxg3+ wins.

B) 40.g3 Rd2+ 41.Kh3 (41.Kg(h)1 Ra1#) 41... Rh2+ 42.Kxh2 Ra2+

B.1) 43.Kh3 Rh2+ 44.Kxh2 Qxg3+ and stalemate or perpetual along the third rank.

B.2) 43.Kg1 Qxg3+ 44.Rxg3 (else mate next) 44... Rg2+ and stalemate or perpetual along the second rank.

B.3) 43.Kh1 Rh2+ 44.Kg1 (44.Kxh2 Qxg3+ transposes to B.1) 44... Qxg3+ 45.Rxg3 Rg2 transposes to B.2.

C) 40.Kh1 Rd1#.

Earlier, as <abuzic> stated, white missed a forced mate starting with 39 Qxh6+, seeing 39...Qh7 40 e7.

click for larger view

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39..............Qf8
40.e7 Qb8+

<if 41.g3 Rd2+ 42.Kh3 Rh2+ 43.Kxh2 Ra2+ 44.Kh3 Rh2+ 45.Kxh2 Qxg3+ 46.Rxg3 Draw by stalemate>

Up to 32 ply, but no longer at 33 and 34 ply, ​ 36. ... Rdd3 ​ gives a negative eval, so after Rdd3 it seemingly should be _white_ who needs to play fairly-well to draw. ​ ​ ​ Nothing else gave a negative eval at any decent depth. ​ ​ ​ Lots of moves were such that they evaluated to [+0.00] at every decent depth, and Rdd3 also evaluated to [+0.00] at depth 33 and 34.

At 35 ply, in addition to the played ​ 37. Qg6 , ​ Qf2,Qg4,Qf4 also give a [+0.00] eval.

At 32 ply, ​ 37. ... Rg8 ​ and ​ 37. ... Raa8 ​ both give a [+0.00] eval. ​ ​ ​ Rg8 was doing that at every decent depth; Raa8 only started that at 31 ply.

At 31 ply, ​ 38. Bxh6 ​ evaluates as by-far the best. ​ ​ ​ The lines it evaluates as next-best are ​ Bmove Ra8 Bxh6 .

At 31 ply, ​ 38. ... Ra7 ​ evaluates as best, and Kg8 evaluates as unique-_next_-best.

39. Qxh6+ ​ mates in 8, with main line ​ ​ ​ 39. ... Qh7 ​ 40. e7 Rh3+ ​ 41. gxh3 Rd2+ ​ 42. Qxd2 ​ . ​ ​ ​ ​ ​ ​ ​ ​ 39. g3 ​ evaluates as unique-_next_-best.

As the annotation says, ​ 39. ... Qc7+ ​ draws. ​ ​ ​ Qf8 is unique-_next_-best.

At 27 ply, ​ 40. e7 ​ evaluates as by-far the best. ​ ​ ​ g3 evaluates as unique-_next_-best, but its evaluation favors _black_ much more than the current evaluation favors _white_.

40. ... Qb8+ ​ is the only move that doesn't result in white winning with mate-in-at-most-. ​ ​ ​ Rh3+ is unique-_next_-best, with main line ​ 41. Kxh3 Rd3+ .

41. Rg3 ​ gives white significant winning chances. ​ ​ ​ g3 is unique-_next_-best, and lets black draw by stalemate as in the puzzle.

Now, to essentially-repeat and then significantly expand on my previous comment here:

With

41. ... Rxg3 ​ 42. e8=Q+ Qxe8 ​ 43. Qxe8+ or ​ ​ ​
41. ... Qxg3+ ​ 42. Qxg3 Rxg3 ​ 43. e8=Q+

followed by ​ 43. ... Rg8 , ​ one gets the position

click for larger view

. ​ ​ ​ In that position, Qxc6 immediately would allow Rxf5 attacking h5, which will, one might say, be difficult to defend. ​ Accordingly, at 31 ply, Stockfish evaluates Qe6 (threatening f6), as by-far the best. ​ After Qe6, at 28 ply, Stockfish evaluates Rf8 (defending f6) as by-far the best. ​ _Now_, with the rook no longer attacking g4, Stockfish evaluates Qxc6 as unique-best at 32 ply. ​ That yields the position

click for larger view

. ​ ​ ​ In _that_ position, black obviously needs to do something about the attacked Rd5. ​ At 35 ply, Stockfish evaluates Rxf5 (eval +2.06) as unique-best, with Rdd8 and Re5 as the two next-best moves (eval +2.18). ​ The reason Rxf5 isn't obviously much better is it lets white fiarly-easily use g6, both for Qg6 threatening h6, and for Kg6 threatening both h6 as well as possibly Q_7#.

I haven't tried playing this out, but I believe the defensive strategy "double the rooks on black's own 7th or 8th and then just shuffle the non-f-file rook" would lose to either [the c-pawn being pushed while supported by both K&Q forcing black to exchange the rooks for the Q&P] or [white sacing the Q for an R, in turn forcing black to sac the remaining rook for the c-pawn], giving white a won pawn ending.

Accordingly, consider Rxf5. ​ At 32 ply, Stockfish evaluates g4 as unique-best for white. ​ That gives the position

click for larger view

. ​ ​ ​ From there, at 36 ply, Stockfish's top two lines correspond to two different strategies:

(+2.10) Rg5, attacking g4 and preparing to double on black's own 7th

(+2.34) Rf2+ Rc2, so black can check horizontally and the c-pawn will remain under attack even after that pawn moves

.