How would you like to spend an afternoon dangling 450 meters above the ground in a metal basket with room for only two people?

For Takuma Tachibana, it's just another day at the office.

"I've always liked high places," says the 32-year-old, as he prepares for another shift cleaning the windows of the world's tallest tower, Tokyo Skytree. "I've never thought of it as being anything scary."