Nantai-san is a prominent extinct stratovolcano on the shore of Lake Chuzenji-ko in Nikko National Park. The peak is sacred and is also known as Futara-san. The middle shrine of Futara-san sits at the foot of Nantai-san, and is where the standard route up the mountain starts. On the summit sits the upper shrine of Futara-san. (The lower Futara-san shrine sits in the city of Nikko and is part of the UNESCO world heritage site).
From locations around Lake Chuzenji-ko, Nantai-san appears as a pretty almost perfect cone.
Great views can be had at the summit, of Lake Chuzenji-ko, and the peaks of Nikko National Parks.
Lava flows from the early stage of the construction of Nantai volcano dammed up the Daiyo River, forming Chuzenji-ko. The dramatic Kegon waterfall plunges over this barrier, and is the top attraction in Nikko National Park.
Nantai-san is within the confines of Nikko National Park, the oldest national park in Japan. From the city of Nikko, take the Tobu buses bound for Yumoto from the central bus station that is just beside the Tobu Rail Station. Alight in front of the Futara-san shrine by Lake Chuzenji-ko. The bus journey takes about 1hr.
The most convenient way to get to Nikko from Tokyo is to catch the Tobu trains going out of Asakusa station. A good deal is to get a "All Nikko Pass" (4400yen) that allows you a return trip from Nikko and unlimited local bus travel at Nikko over a four day period, including buses going to Yumoto.
The Futara-san shrine owns the mountain. You have to pay 500yen at the shrine for the privilege of climbing the mountain.
When to Climb
The official climbing season starts on the 5th of May and ends on the 25th of October. Early in the season, snow still covers the upper reaches of the mountain and snowshoes may be needed. By mid June, the snow should be gone, and its just a normal hike up.
Normal Route Description
The normal route starts from the Futara-san shrine by Lake Chuzenji-ko. This is a popular route and sees quite a bit of traffic. There is an elevation gain of about 1200m from the shrine to summit. 3-4 hrs is the estimated time of the climb for a hiker of average fitness.
The climb starts with a flight of stone stairs from the shrine. The path then continues up along well marked trails amidst trees up till the 3rd station. A tar road switchbacking up the mountainside leads up to the 4th station. From the 6th station to the 8th, there is scrambling up rocks, but the path is always well marked. Above the 8th station the gradient lessens. The last 100m are on loose red volcanic soil.
There are small shelters at the 5th, 7th and 8th station that I assume people can camp in if they so wishes.
External LinksNikko Tourist Association
Blog page of a guy who climbed it in early may: