The Origin of Japanese Buddhism

I went to a Buddhist memorial service today for the first death anniversary of my late uncle. It's been a long time since my relatives met each other. I might disrespect my uncle, but it was a good opportunity. He brought us together.
We held the service in a Shingon Temple. A monk chanted Buddhist mantra in Sanskrit, Buddhist scriptures in Japanized Chinese, and hymns in Japanese.
Buddhism was introduced from India through China, and it was Japanized in Japan. Japanese Buddhism has remained of Indian and Chinese origin until now.