The best visit to Oze National Park can be made during the peak of autumn season, where you can enjoy the yellowish or brownish grass at Ozegahara Marshland, together with the colorful fall foliage of the surrounding mountains. Most of Oze National Park lies within Gunma and Fukushima prefectures. A one-day trip from Tokyo would be possible, but I recommend taking the night bus and spending one whole day for hiking. The track is quite flat from Hatomachitoge to Ozegahara, but somewhat difficult for beginner hikers if you're planning to go all the way to Ozenuma from Hatomachitoge. Staying overnight in one of the lodges would also be a good option.
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