Hokkaido accounts for about 20 percent of Japan’s landmass, and it has the lowest population density of the country’s major islands. This northernmost part of Japan has long attracted domestic tourists, but American visitors are still fairly novel. That will surely soon change, especially in the ski-resort areas of the island’s southwest, where several new luxury properties have opened or are in the works, including everything from large, full-service resorts to intimate hideaways. The Niseko area receives more snowfall than almost anywhere else in the world, and it’s often the powder prized by skiers. In summer, caldera lakes and forested mountains invite scenic boating and hiking excursions. In autumn, the trees put on a colorful show rivaling that of New England. And soaking in the mineral-rich onsens (hot-spring baths), available in all of our recommended properties, is divine at any time of year. Sapporo’s New Chitose Airport has numerous connections to other cities in Japan, and a bullet train connects Tokyo with Hokkaido’s southern city of Hakodate in about four hours.