A few years ago I went to Japan on a high school exchange program. During our P.E. at the school I was assigned, the guys surprisingly wore a lot of square cut briefs as opposed to the baggy board shorts I had heard were becoming more popular. While the square-cuts are somewhat hot, they don't beat speedo briefs, of which there were none
Not sure what the swimsuit style is right now. Although brief-style swimwear isn't frowned upon, I hear boardies are dominating the scene in Japan.