From The Giant: The Definitive Obey Giant Site
From Supply and Demand, pg. 216:
There’s an 11-story building in Tokyo across a plaza from one of the busiest subway exits in all of Tokyo (and probably anywhere else in the world). I went up to the roof and leaned over, using a long extension pole to paste an eight-foot icon face. It only ended up staying up for about a week, but it was long enough for hundreds of thousands of people to potentially see it.