His own words:
“I mentioned before that I like films that are set up like TV dramas. This is partly because I’ve always had the desire to turn into all sorts of different people. So personally, I don’t get off just having sex with somebody. I continue working in this industry not because I like starring in adult films, but because I am given the opportunity to act in various roles. The appeal for me is in the fact that I can play different people, not that I can boast about my acting skills. Consequently, most of the films that I’m in have a proper plot and narrative.”
Original Source: http://www.weirdasianews.com/2008/10/26/74-yearold-japanese-porn-star/#
Japanese seems to have cracked the code on "Health, Wealth and Happiness"