nagano japan snowboarding

Where is the best place to snowboard in Japan?

I thought in Japan, where I had to go snowboarding. I capacity intermediate and want to find the best place with steep hills and snowfall Nice with not many people around. I would also to experience Japanese culture and not be too Western. I thought to Niseko or possibly one of the mountains of Nagano. To summarize I want the territory of snowboarding best open spaced.