Baseball is just as popular in Japan as it is in the United States and, as in the US, Japanese baseball starts young. Wherever you go in Japan, you will see - and especially hear - baseball being practiced on school playgrounds.
But Japanese baseball has the typically Japanese twist of being team-oriented in the extreme, and being bound by conventions. When it comes to form, you will never see any moves made that are not strictly according to the textbook, and the element of ritual when it comes to in-team and inter-team interactions is very strong.
Check out aspects of the above in this video taken of Japanese elementary school teams having a match in Tokyo, not far from one of Japan's hallowed baseball venues, Tokyo Dome. Once the game is over, every bit as much energy is expended on the post-game rituals as on the game itself, and the hierarchy of (adult) trainers/managers and (student) players features very strongly.