The 2309-square-kilometre Daisetsu-zan National Park (大雪山国立公園) offers a spectacular range of gorges, hot springs and mountains – including Asahi-dake, the island’s tallest peak – crisscrossed by hiking trails which could keep you happily occupied for days. Tourism in the park is generally low-key, especially at the wooded and remote Asahidake Onsen. Sōunkyō Onsen, on the northeast edge of the park, hosts the bulk of tourists, though a tasteful redevelopment has made it much more attractive than most hot-spring resorts. The highlight here is the gorge, a 20km corridor of jagged cliffs, 150m high in places. In July, the mountain slopes are covered with alpine flowers, while September and October see the landscape painted in vivid autumnal colours; these are the best months for hiking. During the winter, both Asahi-dake and Kuro-dake in Sōunkyō are popular skiing spots, enjoying the longest ski season in Japan (usually Oct–June).