More tea whisks - there are 120 different shapes it seems. Depends on the school. "During the 36 years that Mr Kubo has been an artisan he has been in a constant dialog with bamboo and knows his material so well that he can tell by the sound of trunks being split whether the worker is doing it right. Sure enough, when he calls out to one of his apprentices, "That didn't sound right!" they apologize and try again."