H. G. Muller wrote on Wed, Mar 7, 2018 10:26 AM UTC:
Usually it is the narrowest dimension that counts, although the largest dimension will then affect how long it takes. When you can push the bare King towards the small edge, you can just repeat doing that as often as is necessary. (For symmetric pieces. With asymmetric pieces it is more complex.)
Just to be sure I checked it out, and the WAD on 12x8 can force mate in maximally 37 moves. Even its weaker cousin the WD can force mate there (43 moves).
Usually it is the narrowest dimension that counts, although the largest dimension will then affect how long it takes. When you can push the bare King towards the small edge, you can just repeat doing that as often as is necessary. (For symmetric pieces. With asymmetric pieces it is more complex.)
Just to be sure I checked it out, and the WAD on 12x8 can force mate in maximally 37 moves. Even its weaker cousin the WD can force mate there (43 moves).