Hindu Gods came to Japan before Buddhism. There are many ancient Temples/Shrines in Japan, which have Hindu god Idols.

Method of Puja in Japan is almost similar to Hindus. Every Temple in Japan has unique symbol, derived from Sanskrit Siddham Scripts (बीज अक्षर).

Shivling at Toganji Temple in Nagoya

It was built by the brother of Nobunaga Oda, the great Samurai of ancient Japan, as a memorial and grave to his father, Nobuhide. It seems like a Hindu Temple with Deities of Goddess Saraswati (Benzaiten (弁才天, 弁財天)), etc but later got occupied or converted into Buddhist shrine.

Japanese Read 生命之根源 “Seime no Kongen”
Seime = Life
Kongen = Origin
English Translation; The Origin of Life

Shivling at Toganji Temple in Nagoya

Hindu Goddess Laxmi Worshipping in Japan :

Kichijōten 吉祥天, Kichijō ORIGIN = Laxmi (HINDU)
Goddess of Prosperity, wealth, Beauty, Fertility Japanese

Kichijōten 吉祥天 is wife of Vishnu (Viṣṇu) Bichuten 毘紐天 (Bichūten)
Kichijoji in outskirts of Tokyo literally means Town of Goddess Laxmi.