Although I am a winter child, autumn is my most favorite season and I am a big fan of autumn leaf viewing as well as hiking in this season. If I have to recommend only one autumn hike in Japan that could take anyone’s breath away and suit any level of fitness, my answer is Kamikochi in Chubu Sangaku National Park, Nagano Prefecture.
To be fair, there are more easily accessible places to hike in fall and if you don’t live in Chubu region, Tokyo, Osaka, or Kyoto, going to your local spot will save more time and cost. That doesn’t mean Kamikochi is super expensive or difficult to reach though. Home to some of Japan’s most imposing mountains or Northern Japan Alps (including Japan’s third tallest peak or the 3,190-meter tall Mount Okuhotakadake), Kamikochi is also the country’s birthplace of recreational mountaineering. The valley remains as pristine as can be with tourism by forbidding private cars in the area except for authorities and those with special permission, so it offers some of the country’s ultimate waterscapes and is one of Japan’s Eight Most Scenic Landscapes (Nippon Hakkei) as well.
Kamikochi can be an easy weekend escape, a not-too-difficult-but-extremely-enjoyable adventure, or even a strenuous multi-day trek as you desire and design. I will categorize my Kamikochi trip as a not-too-difficult-but-extremely-enjoyable adventure that included walking the easy trail.