I think it should be changed, you're really only supposed to place 5 pieces. In fact, as many players know who play at other sites, one of a players DEFENSES is to force a sixth piece placement, since it is not a win.On the other hand, i believe i have only won a handful of games w/ 6 pieces, it doesn't really happen all that often.

13x13 at IYT rarely fills and 15x15 pro version is even rarer...i've personally never seen it happen....so 15x15 would be a good size...20x20 is more of a "Go" size.