Ken is your sensei thinking of going into tsumi ai no kurai? That set is nuki and noto intensive and often done with blades rather than bokuto but I always assumed one would use kendo no kata blades.

One of my companies (got two now) is looking into getting such things produced in soft or spring steel with no edge so that we can (hopefully) get dents rather than chips. I'd test them thoroughly on tsumi ai no kurai myself before putting them out there so you won't see them next week.

On breaking blades and bokuto I always like to tell folks who want something unbreakable to go swing a baseball bat at a telephone pole and if they can do it without breaking the bat I'll use the bat to make their bokuto.

Kim.