Tom, what you said on a similar post,about software engineers might apply here too.The center of gravity must be inside the base in order for something to lean without falling over. So, either he has packed a huge amount of lead in and around his shoes, ankles and lower legs, or he has some way of hooking his shoes onto something, either a grate and hook of some sort, velcro or maybe even an electromagnet embedded before he does his trick. His shuffling walk suggests very heavy shoes.
Of course, today there are all kinds of video tricks and he may just be suspended on a wire that is green screened out and the passers by are shills. The balloon stunt has to be a wire and I'll bet a new Phillips head ratcheting screwdriver that it was a setup. He probably has a harness like the old lady who did the Tinkerbell flight over Disneyland all those years. No, she was NOT suspended by her teeth.
Don't mean to be a spoil sport, just like to figure things out. Still, it is amusing to watch. There seem to be a lot of off the wall game and candid camera type shows in the land of the rising sun.
Speaking of Disneyland has me recall a time when a friend of mine's tiny little sister portrayed Minnie Mouse at the Anaheim Disneyland. The brother often had "naked hot tub" parties, so I have the distinction of sitting naked, sipping a toddy with Minnie Mouse, who was definitely not mousy. She worked there for a couple of decades and took dance and pantomime classes to raise her standing so she wound up traveling for Disney for special appearances. Not Japanology, but a delightful memory from half a lifetime ago.