Here are a few of the animal sanctuaries in Japan. Note they may not be vegan.
AnimO Animal Sanctuary (English)
Honey’s Farm Sanctuary – Instagram (Japanese)
Moo Mow Garden (Japanese) – A farm sanctuary for the cow survivors of the Fukushima disaster.
Open Sesame (Japanese) – This farm animal sanctuary in Kumamoto, formerly a horse rescue, was formed in 2018 and houses horses, a pig and chickens.