Hi Joanna, Welcome to the Myoko Kogen Ski Community

As the previous poster said, March should not be a problem at all. In fact next season there will be a new BASI Ski and Snowboard Instructor Course taking place in Myoko and that will run up to late March sometime.
I've boarded here in early May some years.

I think you could book with some confidence.

Cheers, MG