A lot of Hindu culture has gone to Japan along with Buddhism.
I remember my visit to Nara and the famous Todai-ji Buddhist temple there. It has a huge bronze statue of Buddha as the main object of worship. The details in my mind are somewhat hazy as this happened several years ago but I recall visit to a museum nearby. It held several pictures, statues etc, all, as I recollect, belonging to the Imperial Family. I was stuck by the resemblance of many of them with Hindu deities. Their 'Japanized' names were clear derivatives of the Sanskrit names that we use till today.
I found the same thing in Mongolia.
The same is the case with Thailand too. I was amazed to see in a public square a statue of our own Lord Shiva, albeit with a Thai name. The Emerald Buddha Temple and the Palace Complex in .Bangkok has the story of Ramayana painted on the wall, though Rama there does not look Indian but Thai!!..We have here close to our house an outlet of the Thai restaurant chain 'Spring Rolls. In its entrance, as a part of the decor, is a copper-statue of the four-faced Lord Brahma.
I have also read that in Thailand there exists a class of families called as Brahmins. Their numbers are dwindling in modern times but their importance is seen in rituals connected with the Royal Family such as in coronations. Apparently, they have the exclusive privilege of presiding over such rites, exactly as Raj-purohitas would do in India.
Arvind Kolhatkar