[Tsuwabuki]

I look like I could easily be underage, and I am always carded in the US. I even had one place who was certain my ID was fake, and I had to produce my military ID to back it up.

The only place I have ever been carded in Japan is when I went to a bar near a base, given the junior enlisted that are not of age. When the bouncers and bartenders are Americans too... Well you get the picture. But I have never been carded anywhere else, and the general presumption is if you're here, by yourself, then you are of age (minors don't travel alone! gasp!) and not a single one of my underage friends who tried had issues, as long as they didn't wave the tourist flag around, I think the barkeeps thought they were English teachers, and thus, definitely of age.