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No.508 |
Original Problems, Julia’s Fairies – 2014 (I): January – April →Previous ; →Next ; →List 2014(I) Please send your original fairy problems to: julia@juliasfairies.com |
No.508 by Paul Rãican – A very interesting Retro-Miniature and the 2nd Proca Retractor published on JF! The problem shows that there’s one more successful composer of Proca Retractor to the list given in the comments of No.495! (JV)
Definitions:
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. [The default Calvet type (not usually specified) allows captures on the rebirth square, while the rarer Cheylan variant (which, if essential for soundness, must always be specified) excludes them. Many problems can be of either type.] (def. from Fairings 34)
Proca Retractor: In 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. Proca is a defensive retractor. Given a choice, Black will retract those moves that avoid or delay White’s goal. Black may defend by mating White through a forward move, if such an opportunity exists after one of Black’s retractions. Unless otherwise specified, forward defense is the default condition of Proca retractors. (def. from StrateGems, http://strategems.net/sections/variant-definitions.html)
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No.508 Paul Rãican
Romania
original – 05.03.2014
In the memory of W. Dittmann
 -10 & s#1 Proca Retractor (3+4)Anti-Circe Solution: (click to show/hide)
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Interesting how Black is forced to block 4+1 squares around his king, to allow the selfmate.
I assume the computer test is less than 100% sure – Pacemaker cannot always decide if a retraction leads to a legal position; right?