The “H” mark on the roof of a high-rise building in the city center is not a regular helipad, but an emergency takeoff and landing site.
This is a place used by helicopters in case of an emergency, but most of the buildings have never been used before. For private helicopter transportation, only helipads of a certain size and located on safe plateaus away from residential areas can be used.
When using a helicopter, please understand the situation in Japan.