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Comment by microtherion | Hacker News Reader

The Hasek study in #2 is bugging me: Why can't Black simply play 1. ... Rh8 ? It looks to me like this would gain the one crucial tempo to win the game. None of the discussion of the study I've found seems to consider this move (And the online analysis engines are useless, as they don't properly understand that the original line is a draw, as the article notes).

ETA: Corrected typo, I originally wrote 1. ... Re8, which does not accomplish anything.

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I think white just continues moving the king toward the center -- if black plays waiting moves, white can bring the king to c1-d1-e1 and then shuffle the king between e1 and f1. Eventually white will sacrifice the rook in the same pattern as the main line, and then play Ke2 -- there's no "wrong" square for the white king to be stuck on such that Ke2 would be unreachable, so black doesn't gain anything from the extra waiting moves.

Ah, sorry, I had a typo, I meant 1. ... Rh8, after which the rook sacrifice does not quite work the same way anymore. I agree that 1. ... Re8 does not help.

Ah, understood -- I spent some time trying to figure it out after seeing your clarification. You are right that if you try the same rook sac technique, white won't be able to get the white king over in time to defend g2.

It turns out there is another very impressive move white needs to spot: after 1...Rh8, white needs to find 2. Rf8! and now black has to either trade into the drawn king and pawn ending, or take the rook and give back the tempo that's just been saved. Now the white king is in time again. Quite a move, that should be listed as a sideline in the puzzle for sure!

Brilliant! That's the move I was missing.

Do you mean the Hasek puzzle which starts Kb1 for white? Rh8 doesn't change the approach for white here, in fact the move order is exactly the same. You want to block the rook with the king for one move so that the white king has enough time to protect g2 before the rook arrives.

So move order (as I see it) would start:

1. Kb1 Rh8, 2. Rh6 Kxh6, 3. Kc1... etc.

No, if you try that line, you will find that black gets to h2 one move earlier because its king did not move to g7 first, and therefore the white position collapses. But trykondev found a correct answer 2. Rf8!

Ah you're correct, my bad!

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