No.619 (KW)

No.619 by Klaus Wenda – Proca retractor with a rich content! (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)

Anti-Circe without FD (explanation by the author): the abbreviation FD means Forward Defence. Should Black be able to reach the aim of the play forward (#1, s#1) earlier than White the w attack is refuted. Sometimes such Forward Defences are, like here, unavoidable in a scheme. In those cases it´s a valid convention that the author – as it is done here – expressively excludes a FD already in the stipulation of a defensive retractor.

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)