Skis/board on train or plane

Hi, is it a problem to go on a train from Tokyo to Niseko with Ski/Board-bag?
Do i need to check it in? Any excess allowance?

How much kg is the allowance on domestic planes?
I have 12kg ski/board equipment and 10kg bag and 10 handluggage.
better with train?
thx

I don't recommend the train. It is a very long journey with multiple transfers, and you will need to find a space for your large luggage on each train again, which can be uncomfortable. In terms of regulations, you are allowed to bring skis and a bag onto trains, though.

A domestic flight would be considerably more convenient. The skis can be checked in for free, while a small 10 kg bag can be brought on board of the plane. From the airport you could ride a bus to Niseko, which also has free storage for the skis.

A last option to consider, and my personal recommendation, would be to send your skis to Niseko by delivery service. Possibly from Narita Airport right after arrival in Japan, although it depends on your specific itinerary. I think the cost is less than 3000 yen, and it is clearly the most convenient option. More details:
http://www.japan-guide.com/e/e2278.html

We have sent two boot bags, a large ski bag (two pairs of skis) and a large bag of ski gear within Honshu for around 4000 yen total (one way).
When we have turned in our gear the night before going home (say around 1700), it always arrives at our house before we get there (last time, 1300). So it's a very quick and economical alternative. Of course it's more to go to Hokkaido but really worth it to not have to bother carrying it yourself.