Tuesday’s 5-second tactics

“Time is a storm in which we are all lost.”
― William Carlos Williams
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WHICH PAWN TO QUEEN?
Aaron, Deepak (2320)

fm Eckert, Doug
The North American Open just the other day. Position after White’s 31st move (31.Rb1). White had tried hard to complicate the game but everything has failed: his attack on the Kinside has not yet materialized, while on the Queenside he is busted, the Black pawns unstoppable for much longer.
31…Pxa3!!

The strongest move! Black offers his Rook on b8, believing (correctly) that his a-pawn and c-pawn now become monsters. White has little better than to take the gift: 32. Qc2 Rxb1 33. Qxb1 Rc7! and the pawns will advance regardless of what White does anyway.
32. Qxb8 Qxb8 33. Rxb8

Which pawn to advance: the a-pawn or the c-pawn?
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The choice is not as simple as it at first appears. Infact, only one of the immediate pawn advances wins, while -SURPRISINGLY–the other leaves Black desperately trying to hold on for dear LIFE! After the game it was established that the correct continuation was to advance the c-pawn. Even so, it is still not without some tricks:
33… c2! NOW if 34. Rh4!? –threatening mate with Rxf8+ followed by Rh8++–34… c1=Q+ 35. Kh2 Rc7! defending the threat while the Black Queen also stops any Ng5 nonsense, a point that we shall soon see can be very important; Black wins easily.) INSTEAD, if White would continue 34.Rc8 a2! 35. Rh4!? (What else?) Here Black must be carefull not to get greedy: 35… a1=Q+ 36. Kh2 c1=Q? (SEE DIAGRAM BELOW)

WHITE TO PLAY AND MATE IN TWO MOVES!
Instead, simply 35…c1=Q+! 36. Rxc1 (forced, removing the mating threat) 36… Nxc1 when Black wins easily with his a-pawn.
BACK TO THE GAME CONTINUATION:
33…a2?

Ofcourse, it is difficult to criticize White for playing this move: neither Rook can prevent the pawn from promoting. Never the less, after this move the advantage changes side immediately, leaving Black with a difficult struggle to hold. I assume that Black simply overlooked White’s tricks …
34.Rh4!

Threatening mate in two starting with Rxf8+
34… a1=Q+ 35. Kh2

The mate threat continues and now Black must deal with it. The position is fascinating! As Black chose to promote his a-pawn instead of his c-pawn, White has an extra Rook in play, while the Black Queen on a1 does not cover the vital square g5. The importance of this can be seen from the following variation: 35… Rc7 (DIAGRAM)
Hoping for 36.Rxf8+? KxR 37.Rh8+ Ke7 and the King escapes. HOWEVER, White has a forced mate with 36. Rh8!! Kxh8 37. Rxf8 Kh7 38.Ng5+! (The point of why the Black Queen should be on c1) 38… Kh6 39. Ndxf7+ Rxf7 40. Nxf7+ and mate to follow!
SO BLACK INSTEAD PLAYED:
35… Rxe5! 36. dxe5

Black has dealt with one of the mates (now …Rxf8+ and …Rh8+ will allow the King to escape to e7) and must now deal with the other threat (…Rh8+ followed by …Rf8+ and …Ng5+). Absolutely necessary is now 36…Qc1! , covering the g5- square), though after 37. Ne4! Qa3 (37… c2 38. Rh8+) 38. Nxc3 Nxe5 39. Nxe5 Qxc3 40. Re8 Black is not out of the woods, and it is conceivable that the two Rooks will beat the Queen in the long run. However, this was Black’s only chance.
INSTEAD, probably fatigued by the sudden turn of events, Black erred and immediately lost:
36… f6?

Now White has atleast two ways to force mate!
37. e6! [37. Rh8! Kxh8 38. Rxf8 Kh7 39. Ng5 fxg5 40. Nf7] 37… Qa3 38. Nf7
