Eh, it wasn't too bad tbh, and my employer was one of the most traditionally run in the country.

Mostly the company handing out free step counters to those who wanted it. There might have been some very modest financial incentives given out as well.

Japanese corporate culture is already like this, so it's likely just another pressure like going out nights for team drinks, etc.

It is hell, for someone not used to it or someone over the fat line. Google "Japan fat shaming" for some idea of how abusive they are toward fat people culturally. They're not the only ones though, South Korea and China also have weaker variations of aggressive cultural fat shaming.