H. G. Muller wrote on Thu, Apr 30, 2009 08:17 AM UTC:
I encountered two variants which seem not yet decribed on the CVP:
MiniChess / SpeedChess, wich is played on a 5x6 board, and even has a
described sub-variant MiniChess 2007 which adds a color-swap non-capture
move to the bishop:
http://wiki.cs.pdx.edu/cs542-spring2007/mini-chess/rules.html
The other variant is Twilight Chess, a variant with piece drops:
http://membres-lig.imag.fr/prost/Twilight_Chess/index.html
This latter variant seems of fundamental interest, as it decouples the
problem of handling drops from the problem of how to handle quiescence
search (which makes variants like Shogi and Crazyhouse so difficult): the
holding from which you can make drops is not filled by captures, but you
can move pieces there voluntarily.