Definitions: (click to show/hide)
The -9 & #1 stipulation means: retract 9 moves and then the White (forward) mating move.
Defensive Retractor: In Defensive Retractors, White and Black retract (take back) a given number of moves (-n moves), in order to reach a position in which a forward stipulation (e.g. #1, s#1) is met. Given a choice, Black will retract those moves that avoid or delay White’s goal. Unless otherwise stated, Black may defend by mating White through a forward move, if such an opportunity exists after one of Black’s retractions.
The different kinds of Defensive Retractors only differ in the way uncaptures are handled, of course only legal uncaptures are allowed:
- In Proca Retractors the retracting side decides, if and what man was uncaptured.
- In Hoeg Retractors the opposite side decides, if and what man was uncaptured.
- In Klan Retractors always White decides, if and what man was uncaptured.
- In Pacific Retractors there are no uncaptures at all.
Anti-Circe Calvet (the default type): After a capture the capturing piece (Ks included) must immediately be removed to its game array square (necessarily vacant, else the capture is illegal). Captures on the rebirth square are allowed. Game array squares are determined as in Circe: R, B & S go to the square of the same colour as the capture; Ps stay on the file of capture; fairy pieces go to the promotion square of the file of capture.
No.1076 Andreas Thoma Germany original – 23.05.2016
|
Solution: (click to show/hide)
|
white Ke1
black Kc1
-9 & #1 Klan Retractor (1+1) Anti-Circe Calvet
|
{no animation for Retractors (JV)}
1.Ke1×Pf2→e1 f3-f2+ 2.Ke2×Pf2→e1 f4-f3+ 3.Ke1-e2 f3-f2+ 4.Ke3×Pf2→e1 f5-f4+ 5.Ke2-e3 f4-f3+ 6.Ke1-e2 f3-f2+ 7.Kf1×Pf2→e1 f7-f5+ (f6-f5? Retro-stalemate) 8.Ke2-f1 Pe7×Qf6→f7 9.Kd3-e2
forward Qa1#
The first two men retro with Klan. (Author)
|
Black’s last move must be Pe7xQf6>f7+, the bP does not come from f7 of course.
The problem has quite nice play for just two kings on the board!