Hi, <amadeus>. You understood the point of my post, which I made on the way out the door. Thanks for finding the human short-cut, which closes out the puzzle for me.

< <agb2002> wrote: <johnlspouge: Here is a little extra analysis for the obsessive among us...> Hmm... Do you mean 'obsessive' as a peculiar euphemism for 'Truth seeker'? :-) >

Hi, Antonio. You just had to respond, didn't you? (As, apparently, did I.)

<< <agb2002> wrote: <johnlspouge: Here is a little extra analysis for the obsessive among us...> Hmm... Do you mean 'obsessive' as a peculiar euphemism for 'Truth seeker'? :-) >

Hi, Antonio. You just had to respond, didn't you? (As, apparently, did I.)>> Sorry, your comments are so (mind-) provoking...

But I figured it couldn't be that easy. I at all sorts of weird moves that black might try to trick me, and found some, but none were forced (e.g. 45.b6 Qc8 46.Qd6+ Ka8 47.Qc7? Qa6+! draws -- but better is 47.b7+! followed by 48.Qa6 and I exchange Qs and win).

45 b6+ a8!! 46 xc7 stalemate.

click for larger view

Solution below final diagram...

click for larger view

I thought about the fact that so far this week the puzzles have all been stalemates and that is why I thought that today's puzzle wasn't going to be one.

I have noticed the chessgames folks will sometimes start a week with a theme (though usually not as clear-cut as something like a stalemate theme) and then later in the week the theme gets dropped. That is understandable I guess. So it crossed my mind that stalemate might be in the works here, but then I thought that perhaps the chessgames folks would want people to think about stalemate too much on this puzzle, when in reality there was no stalemate.

I don't think I consciously worked that all out but something like that flashed through my mind.

And of course I was dead wrong.

It is interesting that sometimes the first thing that pops into one's head is often correct (backed up by good calculation of course). Paul Keres and others have mentioned this. If you see a winning move and you calculate out the win, why bother looking at anything else? Of course, I didn't calculate very well, but it seems I was in good company. On the other hand, I tend not to be one of those kibitzers who proclaims "too easy" so at least I have that going for me :-)

<YouRang> thought about b6 straight off, but I didn't think about this at all.

The queen move (to me anyway and apparently to several others) suggests itself because queen endgames are particulary scary to me (and probably to others). There are all kinds of tactical tricks that can happen. Even the thought that there are possible tactics that might be sprung at some unsuspecting moment is enough to get me spooked.

So the idea of trading queens looks appealing. Plus it reduces material and with the queens off, a two-pawn advantage (connected passed pawns no less)just looks so good!

And finally, there is the pin on the white queen and it isn't so easy to think about what that may mean from the initial position.

So I didn't really think much about black's ...Ka8 and if I had thought about it for maybe a split second, then perhaps I would have avoided being a sucker.

Avoiding 45. Qb6?? Ka8, which draws because of 46. Ka6 Qc8+ 47. Ka5 Qc7. The rest is simple:

45. ...Qe5+ 46. Qxe5 fxe5 48.Kb5

Oh, no, wait...

So, I pushed the b pawn. That allows play, still to white's advantage.

The black queen has to retreat. Staying in defense of the king only allows my queen to slip into the row 8.

There is only one square for the black queen to settle, and moving there will allow my pieces to adroitly queen a pawn.

At least, that's my take.

45. Qb6?? Ka8 46. Ka6 Qc8+

The white king can't do anything but retreat to a5.

47. Ka5 Qc7

White to play (45.?) "Medium/Easy"

I almost fell for the trap! I was wondering why this was a two star problem and not easier, and then I found the reason: 45. Qb6+?? -- very tempting because it blocks the check with a check, virtually forcing the trade of queens, leading to a simple won ending for White. Except that it isn't forced! Black has the stalemate resource 45...Ka8! and now if 46. Qxc7 it's stalemate, or 46. Ka6 (only other move) 46...Qc8+! 47. Ka5 Qc7! repeats the position.

Add this to the fact that at first, I thought that 45. b6 was a blunder! I thought that after 45. b6 Qe5+ draws for Black, because it forces 46. Qxe5 fxe5, creating a passed pawn for Black. I was thinking that White couldn't make progress, since advancing the king too far would allow Black's pawn to queen, but a little analysis shows that White queens first (or mates) in all lines:

45. b6! Qe5+ 46. Qxe5 fxe5 47. Kb5 Kb7 (advancing the e-pawn allows White to simply go after it, while White doesn't go after the e-pawn unless it advances, since Black can always play f7-f6) 48. a5 Kb8 (48...f6 49. a6+ is similar) 49. a6 Ka8 50. Kc6 Kb8 (or 50...e4 51. Kc7 e3 52. b7+ Ka7 51. b8=Q+ Kxa6 52. Qb6#) 51. a7+ Ka8 52. Kc7 e4 53. b7+ Kxa7 54. b8=Q+ Ka6 55. Qb6 mate.

So the queen trade after 45...Qe5+ is easy for White. What else? The simple answer is, White wins simply by trading queens at the expense of his b-pawn, advancing the a pawn to a point, then leaving it in favor of gobbling up Black's f-pawns and queening his own f-pawn. For example:

<45.?>

Material: +/\ w: & 4 b: & 3* (ENDGAME) *Black has a doubled-pawn.

Candidates: Qb6†... Qb6†??, <[b6]>

-ML-
I think that the main part of this puzzle is to spot that the proziac seemingly winning 45.Qb6† actually draws on the spot. 45....Ka8!! 46.Ka6 (46.Qxc7 1/2) 46....Qc8† 47.Ka5, and now, 47....Qc7! 1/2 of course. That is a VERY nice stalemate and repetition trap. White should remain on the upperhand, however, with:

<45.b6 Qe7> by any means the best reply: Black would want to avoid Qd6† and Qd8†. If he doesn't, for example with 45....Qg3 46.Qd8† Kb6 47.Qc7†, White trades Queens and wins due to the Black King's occupation with the a-pawn.