Glossary
As a move, a side can swap the squares of one of his own pieces with a similar opposite piece. A swap may not be undone by the opponent on the immediate next move.
654 - Michael Grushko Mat Plus 25, Spring 2007
Retract 2 moves, then self mate in 1 move (Proca Retractor, Messigny-Chess, Köko-Chess)
13637 - Michael Grushko Die Schwalbe 229, February 2008
Last 4 single moves? (Messigny-Chess)
13638 - Michael Grushko Die Schwalbe 229, February 2008
Last 4 single moves? (Messigny-Chess, Hydra-Circe)
