Just a comment - Zen-noh is a huge ag co-op in Japan.
Kubota, Yanmar, likely others, put the Zen-noh trademark on tractors they build for this co-op to sell to its members. So far as I know the Yanmar/Zen-nohs are identical to the tractors labelled Yanmar sold in Japan. I expect Kubota/Zen-nohs have an equivalent Japan-market Kubota twin, also.
Researching this could make finding parts simpler, in particular if there happens to be an American-market twin to your Kubota/Zen-noh.