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| Aug-30-16 | | Oxspawn: There is a slow food movement, (properly cooked meals – post-prandial naps – thank you Italy). I belong to the slow chess movement – brain works slowly and falls asleep at crucial moments. This long answer shows how to take the slow road. The obvious move (Rh7) ‘looks’ wrong to me because of black has three defenders (including the king). I am pushed into persevering because something like this is needed to prevent mate on h1 next move.
Four options for black
36. Rh7 Kg8
37. Qg7#
36. Rh7 Bxh7
37. Qg7#
36. Rh7 Qxh7
37. Qe5+ Qg7
38. Qxg7#
But one I cannot crack
36. Rh7 Qxh7
37. Qe5+ Kg8
Now if
38. Rxh7 Kxh7 black has two rooks and a bishop for a queen
38. Qe6+ does not seem any help after Rf7.
Nor does
38. Qg5+ Kh8
Roll back and look for an alternative…..
36. Rg8+ Kxg7
37. Qg7#
But if
36. Rg8+ Rxg7 what then?
Now I see it…
36. Rg8+ Rxg7
37. Qe6+ Rg7
38 Qxg7#
Time for a nap….. |
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| Aug-30-16 | | Willem Wallekers: Difficult for a tuesday, I tried 37. Rh7+ and 37. f3 before finding the right solution. |
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| Aug-30-16 | | eblunt: When you see that if the white Rg7 didn't exist than white has either Qg7++ or Qe5+ leading to mate, then it's a simple question of which square to get rid if the Rg7 on, given that it must be with check. |
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| Aug-30-16 | | dfcx: Black will play Qh1# next unless white mates first. White would mate with Qg7# if the rook were not there. Getting rid of the rook is the goal. Rh7+ fails to Qxh7, this leaves
36.Rg8+ Rxg8 (Kxg8 Qg7#)
37.Qe5+ Rg7
38.Qxg7# |
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| Aug-30-16 | | leRevenant: If I got it (which I did) Tuesday level is about right. |
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| Aug-30-16 | | patzer2: <YouRang><Basically, 36.Rg8+ could be called a clearance sac. It serves only to get the rook out of the way of the Q+R battery...> True, it is a clearance sacrfice. However, it also employs the decoy tactic (forcing or enticing a piece to move to a specific square, usually with a piece sacrifice involved). In this case the Black Rook is decoyed twice, in that it is forced to move to g8 as a result of White's Rook decoy sacrifice and then again to g7 as a result of the Queen check on e5. |
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| Aug-30-16 | | mel gibson: Easy - just like yesterday's.
Nice one. |
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Aug-30-16
 | | scormus: Nice! Classical Navara, he is not afraid of "tightrope chess" ;) |
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| Aug-30-16 | | patzer2: <Aschultz> <...Navara's Nf4! to get the 2 B's is a pretty sweet move even if it doesn't get a winning advantage according to a computer> Yes indeed! 20. Nf4! is a Sunday level move that maintains White's advantage with a strong tactical threat. If Black takes the poisoned Knight, White whips up a mating attack after 20... hxg5 21. Ng6+ Kh7 22. Nxf8+ Kh6 23. Nxe6 Bxe6 24. Bxg5+ Kxg5 25. h4+ Kh6 26. Rxe6  (#14, Deep Fritz 15). Another example of the precise tactical calculation involved in this game is the possibility 34...Be4 (diagram below) 
click for larger viewHere (diagram above) White forces mate with 35. Rh7+ Qxh7 36. Be5+ Kg8 37. Qxg5+ Bg6 38. Rxh7 Kxh7 39. Qe7+ as play might continue 39...Kh6 40. Bg7+ Kh7 41. Bxf8+ Bf7 42. Qxf7+ Kh8 43. Qg7#. |
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Aug-30-16
 | | gawain: Terrific puzzle!
Too hastily I went for the "almost works" solution of 36 Rh7+ followed by Qe5+. It was the right idea, wasn't it? 36 Rg8+ (followed by Qe5+) is correct. |
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| Aug-30-16 | | YouRang: <patzer2><True, it is a clearance sacrfice. However, it also employs the decoy tactic (forcing or enticing a piece to move to a specific square, usually with a piece sacrifice involved).> Perhaps, but consider this: If our rook were not at g7, we would have simply played 36.Qg7# immediately. We really had no need to force black to move his rook. We only needed to get our rook to vacate g7 such that we still preserving our mating tactic. In my mind, that's a clearance sac. |
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| Aug-30-16 | | kevin86: The key square in this puzzle is g7- but the rook is standing on it. So white desperados the rook and black can be mated in one or two, depending on which capture he makes. |
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| Aug-30-16 | | BOSTER: Chess rules have a small imperfection-pawns can't move back.
This ruins the beauty of something like
f4xQe5. |
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| Aug-30-16 | | vshukla17: What happens if black plays 34 ...Be4? I think black has very good chances for a win! |
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| Aug-30-16 | | drollere: since black has mate on the move, white has to check into the final position. 36. Rg8+ Rxg8 (or Kxg8, Qg7#)
37. Qe5+ Rh7
38. Qxg7# |
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| Aug-30-16 | | jith1207: I was looking at why Black didn't play 34.Be4.. <Patzer2> Thanks for the help, I didn't realize the Be5+ threat of white, which made imperative for the Black to capture the White's DSB instead. You are not <Patzer2>, You are <2Patzer2bTrue>. |
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| Aug-30-16 | | YouRang: <vshukla17: What happens if black plays 34 ...Be4? I think black has very good chances for a win!>
click for larger view
You could say that black has very good chances to win *unless* white finds <35.Rh7+!>, in which case black has very good chances to lose.
click for larger view Black's options:
- 35...Bxh7 36.Be5+, which will be followed up with Qxg5 and mate soon. - 35...Qxh7 36.Rxh7 Kg8 37.Qxg5+ Bg6 38.Rxh7 Kxh7 39.Qe7+ and mate in 4. |
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| Aug-30-16 | | YouRang: OOps - typo in last line of my post above. Not 36.Rxh7 but rather 36.Be6+: <35...Qxh7 <<36.Be5+>> Kg8 37.Qxg5+ Bg6 38.Rxh7 Kxh7 39.Qe7+ and mate in 4.> |
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| Aug-30-16 | | vshukla17: <YouRang> Thanks for trying out 34 ...Be4.
<
In your option 2:
- 35...Qxh7 36.Rxh7 Kg8 37.Qxg5+ Bg6 38.Rxh7 Kxh7 39.Qe7+ and mate in 4.
>
36.Rxh7 Kg8 - Black would go for Kxh7 rather than Kg8 and black has chances. |
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| Aug-30-16 | | patzer2: <YouRang> I have no problem calling 36. Rg8+! a clearance sacrifice, even if it simultaneously employs a decoy sacrifice as a supporting tactical theme. It's not unusual for combinations to employ several tactical themes.
However, as is the case with this "clearance" tactic, they are generally classified according to the most predominant tactic utilized. More important than classifying a combination is being able able to see it. For you thinking of 36. Rg8+ as a clearance sacrifice (i.e. getting the White Rook off g7 to force mate) no doubt made it easier to visualize. For me thinking of 36. Rg8+ as a decoy sacrifice forcing a capture (i.e. forcing the Black Rook to capture on g8 for mate-in-three) made it easier to see. |
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| Aug-30-16 | | YouRang: <vshukla17> Note my correction (in post just above yours). |
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| Aug-30-16 | | morfishine: Beautiful positional clearance sac <36.Rg8+> clearing <g7> for either instant mate at <g7> or mate after 37...Rg7 (to block) then <38.Qxg7#> Beautiful positional clearance sac focusing on the hot square <g7> ***** |
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| Aug-30-16 | | morfishine: BTW: I see no decoy theme whatever since the move <36.Rg8+> wins on the spot "Decoy" does not play into this theme because the focus is on <g7> throughout There is no "Decoying" whatever, which is a completely different theme ***** |
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| Aug-30-16 | | patzer2: <morfishine> A decoy is a move that utilizes a sacrifice to force a piece to a specific square. With 36. Rg8+ we force either the King or the rook to capture on and occupy g8. If the King captures on g8, it's mate-in-two. If the rook captures on g8, it's mate-in-three. While it's true 36. Rg8+ clears the g7 square, it is also true that it forces a piece to capture on g8 which is by definition a decoy. Therefore, 36. Rg8+ simultaneously employs both the clearance and decoy tactics. |
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| Aug-30-16 | | patzer2: Note that on White's 36th move it is not enough for the Rook to simply vacate or clear the g7 square. Any other clearance move over than the decoy 36. Rg8+ loses. For example, Black turns the tables and is winning after 36. Rh7? Qxh7 . So the decoy in moving the Rook to the only winning square, to force a capture by the Rook or the King on g8, is an essential part of this combination. P.S.: By the way, 36. Rg8+! though the best move is not the only solution to our Tuesday puzzle. The alternative 36. f6! forces mate-in seven. |
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+ sac: 34.Rxg7