Why is strength training virtually unknown in Japan?

Since you're a foreigner to Japan, its obviously quite surprising to you, but here's the answer. Most Japanese don't think that being muscular is the ideal image and that if you are to be muscular that you should gain muscle naturally and not from weights. As for muscle in martial arts its a little different if you ever trained in Japan you know that before any teaching is done you go through a pretty intense workout by using your own natural body weight. However it is taught in Japan that as you progress in martial arts the less amount of force is needed. It's all about trying to reach that Musashi level.