I've seen fights where one guy is standing over a guy on his back on the street twice, both in Osaka. The first time was on a very public street and the guy standing was kind of trying to pick his shots, throwing a downward haymaker every 5-10 seconds as an opening appeared. I walked on because I'm foreign and I figure thirty seconds after I said or did anything both of them would be telling a cop who suddenly materialized that I was robbing them or something.

Second time a big fat tattooed very clearly Yakuza guy in a black suit was standing over a scrawny guy in late middle age, maybe fifty, and there was a circle of maybe thirty people watching. Everybody was staring at the Yak and the Yak was staring back at everybody else. The old guy was conscious on his side but not moving. I walked on because I clearly didn't want any of whatever was happening there.