Also known as twin orthodox chess or double-king chess - univeristy project
- each player has two kings and two queens
- 10×10 board
- A player wins by checkmating either one of the opposing kings
The normal chess rules apply, except that kings and rooks can only castle "short" (i.e. with kings shifting two squares toward the nearest corner), and pawns can move one or two steps at any stage.
More info: https://en.wikipedia.org/wiki/V._R._Parton