The 'no downtime' thing really rings true with me .. during my personal time working in Japan I found I'd become accustomed to the fact that it was just 'normal' to be going into the office after a few beers and working another shift .. to the point where, when I returned to California, it was really bizaare to me that, after 6pm, pretty much everyone went home and - except for a few hardcore hackers - life just seep…
You should feel more sorry for your Japanese associates, who spend 12-14 hours at the office every day and never see their families, even though they probably could've gotten their work done in half that time.