...on this tsuba mei? It has me stumped.
On the right side the first character looks like it could be the naga character 長, as seen in Choshu. The second, I have no idea, certainly not shu.
After from the "Tomo" character I am leaning toward a variant of Yoshi 好 as seen on pg. 2011 of Haynes, H. 10179.0 - 1081.0. But that is just a wild guess.