While I'm sure he had some exposure to aiki-ken while he was training at Hombu, when I trained at NY Aikikai (1987-88) I never saw Yamada Sensei pick up a bokken, nor have I subsequently seen do him so on any one of a number of occasions when I saw him at seminars (or, for that matter, in any photos or videos). The late Sugano Sensei's "introduction" of suburi in some classes shortly after his arrival at NY Aikikai was taken as something of an innovation. (And even he discouraged people from making too much of his sword work with the phrase "If you want mochi, go to the mochi maker.").

So there's one.

FL