Dear Grev.
Forgive me if this is obvious and you have already used it but.....https://shibuiswords.com/tsuba.htm You'll have to scroll down a bit.
And from, 'Tsuba:An Aesthetic Study', "The term Bushi tsuba means the Ito school. Though there were many other workers, and several other schools at Edo at this time. These other schools were, for the most part, branch schools that came to settle in Edo, whereas the Ito school was native to that area. They were the most powerful, and largest school in Edo, with influence over all the others who worked around them. The Ito school became so popular that schools as far away as Choshu felt compelled to adopt its style."
All the best.