Re: Is a tsuba necessary?
I went to a Kumitachi (if I mis-spelled that just assume I mis-typed =D) seminar...anyhow, I had the tsuba on. There was at least one whack that would have prematurely ended my participation in the day long seminar, which I was excited to attend and drove 3 hours 1 way to do so, if I hadn't. It still hurt pretty good, but I was able to keep going.
We even practiced a technique that used the tsuba for leverage.