Circe chess (or just circe) is a chess variant in which captured pieces are reborn on their starting positions as soon as they are captured.

See also: http://en.wikipedia.org/wiki/Circe_chess

Andernach chess is a chess variant in which a piece making a capture (except kings) changes colour. Non-capturing moves are played as in orthodox chess. If a pawn captures on eighth rank, it is promoted first and then changes colour.

The game was named after the German town of Andernach, which is the site of annual meetings of fairy chess enthusiasts. It was during the 1993 meeting there that Andernach chess was introduced with a chess problem composing tournament for Andernach problems.

See also: http://en.wikipedia.org/wiki/Andernach_chess