Competitions are played on 6x7 or 8x7 boards in Hungary, otherwise with the traditional rules.
The use of irregularly shaped boards, optionally with forbidden areas (islands), might be quite funny, enjoyed mainly by children.
 
All reversi type games that start from the middle may result in a more balanced fight if played on even x odd boards. An even-numbered distance from the middle of the board will be more favourable for the first player to move, while an odd-numbered distance will be more favourable for the second player to acquire the strategically strongest corner positions.