White to move and win! Can you calculate all variations without using computer?
Chess Daily News from Susan Polgar
Extensive calculation exercise
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White to move and win! Can you calculate all variations without using computer?
my try so far:
1.b7
A) 1…rxb7 2.d8q+ ka7 3.nc6#
B) 1…bxb7 2.d8q+ bc8+ 3.kf6 +-
C) 1…kc7 2.nc6! kxc6 (2…kxd7 3.b8q; 2…kxb7 3.d8q)
3.d8q (3.b8q rxd7+ 4.kf6 rd6+ 5.ke5 +- because of the threats qxa8 and qxd5+) rxb7+ 4.kf6 +- because of the threats qxa8 and after e.g. 4….ra7 5.qb6#
D) 1…kxb7 2.kf8! (2.d8q?? stalemate) 2…kc7 (2…kb8 3.d8q+) 3.ke8 and the pawn passes.
greetings, vohaul
vohaul, as far as your variation A is concerned, the d pawn cannot queen as it is pinned
uuuppps… indeed, a clear mistake! thx
my improved line A) is:
A) 1…rxb7 2.nc6+ kc7 3.d8q+ 3.kxc6+ kf6 with the threat qxa8 +-
🙁 Vohaul
in the meantime i put my variations into Fritz! …:((
A(improved) – C are quite sound but line D) … oh oh oh …
(2.kf8! LOL – much better is … 2.kf8?? – so – the puzzle isn’t solved yet – and i’ll keep both, my keyboard and mouth closed … – a single hint: watch out zugzwang positions after sub-promotions).
a sad Vohaul
its funny cause you dont even have to figure out the right way. just take the rook and underpromote to a rook (to avoid the stalemate) and white creeps in eventually…unfortunately….its just a pragmatic approach ..but I dont think black has much resistence available. just my lazy solution
above comments by Dizzy D
1.b7 Kxb7 2.d8R Kc7 3.Ne6+ Kb7 4.Kf6 Kc6 5.Ke5 with a zugzwang due to 5..Bb7? 6.Rd6#.
1.b7 Kb7 2.Kf8? Kc7 3.Ke8 Kb7!!
Better 2.d8R Kc7 3.Ne6+ Kc6+ (3.-Kb7 see anononymous’ variation) 4.Kf6 d4 5.Ke5 d3 6.Rd6+ Kb7 7.Rd7+ Kb8 8.Rd8+ Kb7 9.Kd6 d2 10.Nc5++
(I didn’t use computer or board — hope it’s correct.)
The variation after 1.b7 Kb7 2.d8R is quite nice, but the variation 2.Kf8 Kc7 3.Ke8 Kb7 is wrong – White has the simple 4.Ne6, breaking the pin and followed by 5.Qd8. Better is 3.-Bc6 4.Nc6 Ra8+ 5.d8Q+ Rd8: which seems impossible for white to win.
Dizzy: “just take the rook and underpromote to a rook (to avoid the stalemate) and white creeps in”
1… Kc7 stops the promotion, which is far more important than taking the new a-pawn after bxa7.