Yes, there are no restrictions in regards to real estate ownership of both land and buildings except for registered farmland. Foreign residents, regardless of their visa status, may purchase property in Japan.
Almost all land in the greater Niseko area is freehold. The exception is Annupuri pension village and some blocks of land in Kutchan town being leasehold.
A tsubo is a Japanese unit of area measurement for real estate. Tsubo are usually used to measure land areas and compare land prices. 1 tsubo is equivalent to 3.3058 square meter (35.54 square feet).
Generally vendors build in some room in their asking price for negotiation. However in a strong market or property in a desirable location, negotiation may not always be possible.