The HN meetups in tokyo might not be as you imagine. :-) Japan is not as startup-friendly as you might suppose based on the amount of technology that comes out of the country, but things are changing here. In the past few years we've seen a lot more interest in entrepreneurship and startups, VC's, and incubators.
We run a casual, low-pressure mixer kind of event about once a month. If you come to Japan, you can follow our blog (http://www.makeleaps.jp/blog/en/) or signup on Doorkeeper to get notified of events. We get lots of visitors from abroad swinging through and we're always looking to help support other startups in Japan or small businesses trying to enter the market here. It's a really good crowd of people.
There's also a meetup for HN readers in the kansai area of Japan if you're visiting there.