Pokémon Go was not launched in Japan on July 20. On July 20 stock of Nintendo dropped 12.1%. McDonald’s Japan has announced that there will be some kind of collaboration when Pokémon Go is released in Japan, such that certain characters will be available at McDonald’s restaurants or some promotional items related to Pokémon Go will be available at McDonald’s. However, Nintendo is saying that such information is not released by Nintendo, kind of saying no comment.
Some sources are saying that server issues are one of items working on before releasing Pokémon Go in Japan. However, Nintendo is also concerned about other stuff. After release of Pokémon Go in the U.S. there have been inappropriate actions/situations reported concerning Pokémon Go players. Such as people not paying attention when walking around playing Pokémon Go, playing at memorial places or museums, walking into a private property, etc.
In the U.S. such actions are considered ignorance and fault of players. However, Nintendo thinks in Japan such actions will be partly blamed on Nintendo for releasing such game to public. Nintendo is concerned about negative impact on Nintendo if such actions were reported by media in Japan. Some are reporting that app makers are working regarding such situations before releasing Pokémon Go in Japan.