When you just travel around just ski resorts such as Hokaido, Nagano or wherever, your luggage does not cause lots of troubles. It just make you a bit tired.
But if your itinerary is like...
It may be an idea that you send your ski gears to the airport using package-delivery service where you leave, Narita/Kansai/Nagoya, after you enjoy skiing.
You may wish to make use of one of the many fine delivery services to forward your luggage and/or skis ahead of you, specifying that they be delivered on a certain date and within a certain time frame. Such services are available, reliable, and generally pretty reasonably priced. Beats the heck out of wagging them around through trains and train stations while trying to ride herd on a pack of young 'uns at the same time.
I have to agree with mike. Coming from Canada my brain is still telling me to carry everything I can with me where ever I go. But after many years living in Japan my brain now has a few gliches and is starting to be re-programed I do it the Japanese way now where or whenever I go anywhere. I just mail everything to a buddies house or the hotel I'm staying at and it always arrives when I say but I usualy just say next day anytime. Its cheap too a pretty big bag or a suit case upto 30kg will run you 2,500 yen not bad an no hassel at the airport or draggin it through train stations. I think its a great price for relaxation and security hassells at the airports. same price as a meal and a beer!