Ive been skiing in Japan for the last 5 years both on the main island Honshu and Hokkaido the northern most island. I have lived in Crested Butte for 20 years now and have not skied lighter , dryer or the amounts of snow that I have skied in Japan. Its blower.
I run trips to Japan in the winters taking people skiing and have lots of information. You might want to go to Professionally Guided Ski Tours in Japan, France, Switzerland, Finland, Alaska, Colorado
and check out my web site. It will give you some answers to many questions.
My back country trip is full for this coming season but have spots on my Niseko trip which is resort based. Drop me an email with specific questions and I will do my best to answer them. I will be over there in Feb again this season and have some stuff I do that is not on my web site.
Some of my deepest days ever have been in the backcountry of Japan.
Check out the you tube footage of some of the folks I took skiing last year,
YouTube - 3pinproductions's Channel