Mt. Asahi （朝日岳）
Last updated: Feb 17, 2025
Mt. Asahi, in Yamagata Prefecture, is one of the most inaccessible peaks in Japan, and one of the most breathtakingly beautiful.
The hike: From the hut at Koderakousen, take the trail heading towards Mt. Kodera (小寺山). The trail wastes no time in gaining elevation, and you’ll be happy for the abundance of fresh water if hiking in the summer. After about 2 hours of climbing, a trail will come in from the right. This leads to Hananukimine (ハナヌキ峰). Ignore this trail and keep climbing on the well maintained path. After another 30 minutes you’ll reach the top of Mt. Kodera. The views will start to open up, but the best is yet to come. Continue for another half hour or so toward Mt. Ko-asahi (小朝日岳). Just before the steep climb to the top, there’s a spur trail off to the right. Take this if you’re feeling lazy, but otherwise head to the top for a sweet view of Mt. Asahi stretching out in front of you. On the peak, the trail from Asahikousen joins this trail, so the number of people should increase somewhat. From here to Mt. Asahi, there’s only one trail and it’s well maintained. Drop steeply off the top of Mt. Ko-asahi, being careful not to slip and fall. After descending to the saddle, the ‘lazy’ spur trail I mentioned earlier will come in on the right. Continue climbing up and up for another 90 minutes or so, enjoying the multitude of alpine flowers along the way. Eventually, you’ll reach Dai-asahikoya (大朝日小屋). This is your home for the rest of the day, as watching the sunrise from “Sunrise Peak” is one of the main reasons for doing this hike. You can camp outside the hut, or stay for the measly sum of 1200 yen. The hut has no food or futons, so bring your own cooking gear and sleeping bag. There’s a water source a short distance away on a side trail. Wander up to the main peak if the weather’s good to watch the sunset. The next morning, wake up early so you don’t miss the action. In the summer, you need to be out of the hut around 3:45am if you want to get a good spot for the sunrise. It’s only a 10-minute hike from the hut to the top, so pack up your gear and take it with you. The sunrise, if the weather is good, will definitely alter your sense of Japanese beauty. The sun comes up behind Mt. Zao, and illuminates the ridge lines of Mt. Iide, Gas-san, Mt. Chokai, Mt. Bandai, and hundreds of other nameless peaks. No utility poles and no concrete anywhere to spoil the view. After taking in the scenery, follow the trail heading to the left, towards Asahikousen (朝日鉱泉). The trail drops quite steeply for the first hour or so, and then enters a beautiful virgin forest, eventually flattening out to follow an amazing river with crystal clear water. Follow the river for about 2 hours or so, and you’ll end up at the Asahikousen, one of the best mountain huts in Japan. Keep your eye out for Japanese mountain goats (Kamoshika), as there are a lot in this area. The owner of the hut is really friendly and makes one of the best bowls of soba in Japan, teeming with fresh organic mushrooms. Oh, and use the hot spring bath while your noodles are being prepared.
When to go: This mountain is completely inaccessible in the winter due to its remote location and the obscene amount of snow it gets. The roads usually open up again in late April, so go between then and early November, but for a snow-free experience, wait until July to complete the hike.
Access: From Yamagata station, take a local train on the JR “Fruits Line Aterazawa” line and get off at Aterazawa (左沢駅), the last stop. Trains are very infrequent, so check the schedule in advance. From the station, take a bus to Asahikousen（朝日鉱泉). The bus only runs from July 23-August 14, leaving Aterazawa station at 1:00pm and reservations are required. You can inquire about bookings when you reserve accommodation at Asahikousen lodge. Click here for the bus schedule. Another option would be to take a taxi to Koderakousen (小寺鉱泉), an alternative starting point for the hike. The taxi is not cheap, though. I did this hike after descending Gas-san, and hitchhiked all the way from there to Koderakousen, so that’s definitely an option for those without a car. The hike described here is a traverse from Koderakousen to Asahikousen, so you can take your pick of trails.
Level of difficulty: 4 out of 5 (elevation change 1320m)
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Hiking in Japan 
August 2, 2021 at 8:04 pm
I agree, this was an absolutely beautiful mountain range. I did it hard on the heels of the Iidensan hike, so if anyone wants to see how to combine the two, please see my post on Iidesan.
Anyways, I started hiking from the unfortunately named Gomisawa (redeemed by the kanji: 五味沢). This was easy and inexpensive to get to from Oguni station (350 yen.)
Click to access north.pdf
I caught the 12:12 bus, which meant I didn’t have too much time to make progress on day one. If you have a tent, there is a flat though narrow clearing near the 蛇引清水 water source that is a good place to camp. The whole day I didn’t see a soul as most hikers seem to approach Asahi from other directions but the path through the forest was breath-taking. The one downside was a series of suspension bridges that were, as of July 2021, in criminal disrepair.
For day 2, my goal was pretty modest, just get up to Mt. Asashi and cool my heels there. There was still some snow, lots of room to pitch a tent neat the hut, a great source of water, and a pretty animated crowd staying in the hut.
By this point the weather started to turn and so unfortunately day 3 was a climb down to Asahi Kosen via Koasahidake and Toriharayama (which looked like it had a fabulous hut.) And just to echo Wes’s comment about the Naturalist’s house (ナチュラリストの家) at Asahi Kosen, the bath and soba noodles were the best. You can also buy tickets there for the bus to the nearest train station (Aterzawa) that will take you into Yamagata city.
July 30, 2025 at 7:52 pm
Check Asahi Kousen and Kodera Campground webs for the latest road info. Afaik the road that connects those two will remain closed for the time being.
Due to this and ongoing roadworks on the last remaining Asahi Kousen road, the eastern approach isn’t used much. But if you do go that way, about 4.5 km ahead of the Kousen is a well marked trailhead that goes directly up to the Torihara Hut. It starts off easy, going over several rather memorable metal bridges, but soon turns into a righteous steep and slippy climb. Takes solid 3 hours with bag to the hut. From there it eases off up until it joins the main route on top of Mt. Koasahi and offers amazing views of both peaks along the way. Some 6 hours total. This trailhead has no carpark, but you could work with the Kousen staff, or start from the Kousen itself and hike either via Torihara or directly towards the peak.
The trail from Kodera carpark is trivial.
All trails, it seemed, are well maintained and even though they suffer from path erosion a bit, it still is a very pleasant hiking overall.
Huts charge 2.000¥ pp pn and the Asahi peak hut is well worth staying in for the sunrise.
All in all I’d say this is another excellent intermediate peak thanks to great paths, abundance of water all along the trails and the peak hut.