Glossary
In Köko Chess (Contact Chess) a move is legal only if departure square is adjacent to any piece, this applies also to the capture of king. E.g. in starting position white cannot advance his pawn for 2 squares, in position wKe6, bKe8 are moves Kd7, Ke7, Kf7 perfectly legal for both sides.
654 - Michael Grushko Mat Plus 25, Spring 2007
Retract 2 moves, then self mate in 1 move (Proca Retractor, Messigny, Köko)
13698 - Bernd Gräfrath Die Schwalbe 230, April 2008 Dedicated to Thomas Brand for his 50th birthday
Proof game in 8.5 moves (Köko, C+)