A couple of years ago we conducted usability tests in Japan as part of a large design project Yu Centrik was taking part in. At the time, we had many questions about what needed to be adjusted in our prototype, discussion guide, and all other test aspects, in order to get the best possible results.
If you are considering conducting usability tests in Japan or in any country other than your own, I recommend reading this short post
. There are critical factors to be considered — interview questions likely being the most important.