Definitions: (click to show/hide)
The -19 & #1 stipulation means: retract 19 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: After a capture the capturing piece (Ks included) must immediately be removed to its game array square (necessarily vacant, else the capture is illegal). 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.
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No.1013 Alex Levit
Russia
original – 25.02.2016
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Solution: (click to show/hide)
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white Kd1
black Kc5 Bb4 Pe6
-19 & #1 Proca Retractor (1+3)
Anti-Circe
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{no animation for Proca Retractors (JV)}
1.Ke1-d1 Ba3-b4+ 2.Ke1xpd2(Ke1) d3-d2+ 3.Ke1xRd1(Ke1) Rd2-d1+
4.Kg2xpg3(Ke1) Rd1-d2+ 5.Kf2-g2 g4-g3+ 6.Ke1-f2 Rd2-d1+
7.Kf2xBg2 Rd1-d2+ 8.Kf1-f2 Ba8-g2+ 9.Ke1-f1 Rd2-d1+
10.Ke4xpe5(Ke1) Kc6-c5+ (position 1st time) 11.Kd4-e4 Kd7-c6+
12.Ke4-d4 Kc6-d7 (position 2nd time) 13.Kd4-e4 Kd7-c6+
14.Ke4-d4 Kc8-d7+ 15.Kf3-e4 g4-g5+ 16.Kf2-f3 Rd1-d2+
17.Ke1-f2 Rd2-d1+ 18.Ke7xBe8 B~-a3+ 19.Kd6-e7 and forward Kd6-c7#
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To my current knowledge, this is a task: the longest Proca Retractor AntiCirce Wenigsteiner. The previous record (18 moves) was held by Paul Raican.
The black King far away from of the edge of the chessboard seems to be a novelty in this kind of problems. Andreas Thoma was the first composer who successfully realized Proca Retractor AntiCirce in Wenigsteiner with bK not initially placed on the edge.
Here, thanks to a draw pendulum, the bK is decoyed to the edge of the board. As typical in this kind of compositions, white needs to employ several successive preparatory plans in order to reach its objective.
A truly outstanding achievement, which will hopefully become a candidate for the WJP 2016 selection!
And as I have just found out, there is longer Wenigsteiner Proca retractor in existence, by AL too:
Alex Levit
Problem Paradise I-III/2016
dedicated to Vlaicu Crisan
Kf1 Ph5
Kb1 Sf1
Anticirce
-21 & #1, Proca Retractor
Is there any information about possible cooks available, please?
Meanwhile, Alex Levit has the record with 23 moves, PP74/2016, Ke1/Ka2 Pe2 Pg5, Proca Anticirce -23 & #1