Starts with the letter 'O'
- ObstructionChess. A new chess variant designed to challenge old strategies and improve your chess play with logical and organic obstructions. (8x8, Cells: 64) By martin rinab.
- Official Football Chess. Variant from the 1960's with pieces replaced by football players. (8x8, Cells: 64) Author: Hans L. Bodlaender.
- Omega Chess. Rules for commercial chess variant on board with 104 squares. (12x12, Cells: 104)
- Onitama. Cards decide how pieces move, perfect information with no chance beyond setup. Author: Mikk . Inventor: Shimpei Sato.
|4 'Game' entries listed||1 'Large board' entry listed|
|1 'Small board' entry listed||1 'Uses cards' entry listed|
|4 'Sold commercially' entries listed|
Total items listed: 4