Talk:Construction/@comment-198.53.96.60-20140627063618/@comment-24980562-20140627074013

Simple. Yamato and Bismarck both share the 4/6/6/2/20 recipe, but for the latter you need either Z1 or Z3 as secretary, otherwise you can't get her. When you use either as secretary, Bismarck gets added to the pool of possible results, so obviously Yamato has a lower chance of appearing because there are now more ships that can appear with this recipe.