Social climbing
Rod is seeking rock to scale:
"We have just moved to Hiroo (in Tokyo) from New York and while they are still on school holidays I want my children to have the experience of rock climbing in a safe environment before going into nature. I know it's a long shot in the heart of the city, but then Tokyo does appear to be an astonishing place."
Indeed it is, and here are two venues specifically designed for wannabe rock climbers: