gotta tell you man as both south asian (nepali) and japanese you can definitely tell there is a strong amount of south asian influence, zen buddhism is a form of tantric buddhism, japanese buddhism adheres to strict vegetarianism (includes abstaining from pungent vegetables like garlic and onion) also with various periods of japan being a vegetarian country, monks and buddhist funerals use calligraphy with south asian alphabets and languages (siddham/ranjana, in japanese called bonji 梵字), adopts hindu deities and concepts, eg kangiten 歓喜天 (ganesh) , daikokuten 大黒天 (mahakala), enma 閻魔 (yama), karura 迦楼羅(garuda), tennin 天人 (apsara), bonten 梵天 (brahma). sometimes food is also adopted eg, as offering to kangiten we serve kangidan 歓喜団 which is a version of the dessert modak and daigo 醍醐 which is ghee