Problem 756: Valdmir Pankov - Helpmate |
![]() 756. Vladmir Pankov (Russia)
07.09.2016
![]() H#6.5 (2+5)
1...Ba7! (1...Bb6?) 2.f2 Kb7 3.f1B Kb6
4.Ba6! (4. Bc4? Kc5 5. Be6?) Kc5
5.Bc8 Kc4 6.d5+ Kd3 7.Be6 Bb8#
Anticritical move of white bishop, staircase of white king, black minor promotion, tempo – move of black bishop, ambush of black bishop, two active square – block, ideal mate, minimal, miniature. (Author)
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Comments
What is the main idea of the problem as a whole?..
Good question! For me the main idea is the black bishop taking the long blocked route to e6.
The nice idea is obvious here, a "nameless pattern", including "ambush", is created by the motivation for a longer route "through" bPd7, instead a shorter one through the empty square d5 (there's no tempo-move, of course).
It's not a "well known name" like "Rundlauf" that makes the content in the following rough example, but 4 moves wasted just to allow only one move 4...Kf4.
White Kg8 Bh3
Black Pg7 Pd6 Kg6 Bh6 Pd5
Stipulation H#6.5
h#6.5
1. ... Bd7 2.Kh5 Kf7 3.Bg5 Ke6 4.Be7 Kf5 5.Bf8 Kf4 6.g5+ Kg3 7.Bh6(Rundlauf) Be8#
However, missing the most crucial simple fact is a rather strange failure.
Author wrote: "tempo–move of black bishop", the program detects no such move and this is true
There is no tempo maneuver in Nikola’s example too (due 5. ... Kf4).
I even made the example showing four moves "wasted" on the maneuver with the only purpose to unguard f4 in the right moment. "Wasting" 4 moves is the consequence and not the purpose.
Tempo play must have the purpose to lose time.
Departure of wBf2 has the vacation effect, crucial for the construction. The complete move 1...Ba7 has the anticritical effect, although with a very impure purpose.
You are right that W1 has "square vacation" departure effect. I updated the program, and now it is does not have that error. This was due the incorrect definition of term “square vacation” in the “Encyclopedia of chess problems”, that states, that square vacation is related to friendly pieces only. Of course, this definition must be corrected.
I am not sure if W1 has the anticritical effect, that is related to the further play. Move 1... Bb6? has negative square obstruction effect, which is avoided by 1... Ba7. I think that the main purpose of W1 is to reach wB the mating square b8.
(For instance, "Analizer" mentions 3...Kb6 as the line opening, which is irrelevant but still a fact. Since this is mentioned, 2...Kb7 could be mentioned as the line closing, also an irrelevant fact.)
Anticritical move is about timing. There is some (whatever) arrival purpose but the move must happen before the line will be closed.
The task for wB is indeed to reach b8/c7 in 7th move but White has lot of time (6 moves) to prepare a convenient access.
It's a fact that wB moves to a7 before wK moves to b6. The "visible" strong reason for timing is the need of immediate vacation of f2.
But the "invisible" intrinsic feature is that the anticritical effect is required in ANY case when bB goes to e6 via a6&c8, even if vacation of f2 would not be necessary. For instance, if wB was on e3 or g1 instead of f2.
Unfortunately, wB is on f2 exactly to avoid the cooks with bBf1-g2-d5-e6 which would allow wB to wait until 6th move (if wB was e.g. on g1).
In the original 756, there's a try
1...Ba7 2.f2 Kb7 3.f1B Kb6 4.Bg2? Kc5 5.Bd5 Kc4??? 6.Be6!? Kd3!? 7.d5 Bb8#
Of course, wK can't reach c4 before it gets attacked by 5.Bd5.
wK could play first and reach d3, still having 2 moves for wB but then, black play (2.f2) would be impossible.
The try fails because White can't achieve both requirements in due time (wK reaching c4 & vacation of f2).
The solution works because both the vacation and the anticritical effect are luckily achieved by the same move.
And that is indeed relevant for this position.
Version: Kb6/3p4/5p2/4kp2/8/5p2/8/6B1 2 solution
1) 1. ... Ba7! 2.f2 Kb7 3.f1B Kb6 4.Ba6! Kc5 5.Bc8 Kc4 6.d5+ Kd3 7.Be6 B:b8#
2) 1. ... Kb7! 2.f2 Kb6 3.f1B Kc5 4.Bg2! Kc4 5.Bd5+! Kd3 6.Be6 Ba7 7.d5 B:b8#
Maybe we have an anticritical move actually in all cases (even in the case of a critical move) when a linemover crosses a square which later another piece moves to, because in such cases we cannot change the order of moves?
I was not careful, since in the context of discussion, the active purpose of 1...Ba7 was already mentioned and my focus was on the timing related to the critical square.
The illustrative version (wBg1 and added bBb8) with two ways to reach the same
mate, greatly helps understanding the essential characteristics of the original
(which allow the solution and not the try (3.Bg2?)).
bB can't go shortly to e6 via c4 because the unguard of c4 would never happen. Such unguard may happen only transiently, between 4.Bf1-g2 & 5.Bd5 or 5.Ba6-c8 & 6.d5.
I hope that in the version, the relevance of critical squares b6&c5 is clear, with regards to 4.Ba6!? or 4.Bg2!?. This is hidden but also present in the original.
The beauty of the idea is in the dynamics of mechanism, governed by the transient unguard of c4.
The version presents the mechanism clearly but with considerable flaws.
The original would be sufficient if the try was mentioned. Author should present the version as the author's comment, to help the audience and the judges to perceive the mechanism.
Also а longer solution is possible: f3->f4 h#7 1. f3 ...
1.f3 Ba7 2.f2 Kc7 3.f1=B Kb6 4.Ba6 Kc5 5.Bc8 Kc4 6.d5+ Kd3 7.Be6 Bb8#
There is my problem with two maneuver black bishop in 4 move: 8/3p4/5p2/2K1kp2/8/8/8/4Bb2
1.Bg2 Kc4 2.Bd5 + Kd3 3.Be6 Ba5 4.d5 Bc7 #
1.Ba6 Ba5 2.Bc8 Kc4 3.d5 + Kd3 4.Be6 Bc7 #
Achievement variants of black positions of mate:
I. Bf1-c4-e6 + d7-d5 ?
II. Bf1-c4-e6 + d7-d6-d5 ?
III. Bf1-c4 (a2,b3,d5,f7,g8)-e6 + d7-d5 ?
IV. Bf1-g2-d5-e6 + d7-d5 !
V. Bf1-a6-c8-e6 + d7-d5 !
This shows a ABC/CAB cycle of W 1/2/3 moves and a reciprocal change of B 3/4.
In comment #12, the version shows a ABCDEF/BCDEFA cycle of W 1/2/3/4/5/6 moves plus a reciprocal change of B 6/7.
Quoting Vladimir Pankov:
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