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| | | (1) Posted by Dupont Nicolas [Saturday, Nov 18, 2017 18:39] | Help reflex series
I’m aware of only one ser-hr example - see the following link page 44:
http://parryserieshub.chessproblems.ca/pdf/DanMeinkingChessProblemCollection2011v2.pdf
I have three questions about this genre:
1) Is there some place where the precise definition is provided?
2) Is it possible to check such a problem? Help reflex is programmed under Popeye (stipulation hr),
but not ser-hr, and I wonder if it is possible to construct a corresponding sstip.
3) The move sequence is of the general form BBBBWB#, and the problem in the link is illustrating the white reflex
(W can’t have the possibility to checkmate). Is there a black reflex during the series too?
As an example consider the scheme:
W: Pb5e2 B: Sg2 Pe3
Does the ser-hrx3 stipulation leads to a solution 1.Sf4 2.Sd5 b6 3.Sxb6, or does a black reflex
1.Sf4 2.Sxe2 occurs, and there is no solution?
| | | (2) Posted by Joost de Heer [Saturday, Nov 18, 2017 20:23]; edited by Joost de Heer [17-11-18] |
Never mind
| | | (3) Posted by seetharaman kalyan [Sunday, Nov 19, 2017 19:07] |
Petkov has given a definition in the following article which seems acceptable.
http://juliasfairies.com/pp-help-self-problems-black/
No.22 in it is an interesting original, though Petkov modestly calls it a scheme.
| | | (4) Posted by Dupont Nicolas [Sunday, Nov 19, 2017 21:08] |
Thanks. Unfortunately the given definition:
"In a ser-hr#n, Black plays a series of n-1 moves, then White forces r#1. The same rules apply as for a regular reflexmate, i.e., White is obliged to mate at any time during the black series, if possible."
is not very clear concerning a possible black reflex, and it is not used in scheme 22 (where wPa7 should probably stands on square b6, though). So the question of the existence of a black reflex in ser-hr looks still unanswered...
| | | (5) Posted by Joost de Heer [Wednesday, Nov 22, 2017 15:33] |
This can now be solved in Jacobi (http://wismuth.com/jacobi/)
| | | (6) Posted by Dupont Nicolas [Wednesday, Nov 22, 2017 19:53]; edited by Dupont Nicolas [17-11-22] |
Yes I know - François and I discussed this ser-hr genre before it was programmed. François decided to also include the black reflex, even if we are not 100/100 sure that it is correct, due to the lack (to our best knowledge) of a full and precise definition of ser-hr. Nevertheless adding the black reflex looks the best option, as the definition for well-established reflex genres asserts that it is bi-sided.
Here is an example checked with Jacobi, showing the existence of both a black and a white reflex:
forsyth 8/8/8/8/5P2/3p4/3P4/s7
stip ser-hrx2
1.Sc2 2.Sd4 f5 3.Sxf5
Jacobi doesn't play 1.Sb3, which would imply the black reflex 2.Sxd2. It doesn't play 2.Se3, which would imply the white reflex 2...dxe3. Hence the unique solution above.
Note that Jacobi is searching only for exact solutions, i.e. of the stipulated length. The scheme above admits a shorter solution 1.Sb3 f5 2.Sxd2.
Note also that if we replace wPf4 by wRh1, Jacobi gives:
1.Sc2 2.Sa3 Rb1 3.Sxb1
In particular the "solution" 1.Sb3 2.Sxd2 Rf1 3.Sxf1 is rejected, although it fits the black reflex definition (black must capture when possible). The reason is that it should be added in the definition "black must capture when possible, and the game is over". I suspect that this important adding (also followed by Popeye and WinChloe) is missing from the original definition as reflex is generally defined for checkmate goal, where "the game is over" becomes tautological.
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