Mt. Sukai (皇海山)

Mt. Sukai, along with Mt. Poroshiri in Hokkaido, garners the dubious distinction of the most difficult Hyakumeizan to access without a car. Those putting in the effort will be rewarded with some wonderful flora and great views.

The hike: There’s a toilet and bridge at the start of the hike, so that’s your clue to park the bike or car. Cross the concrete bridge and take a left up a gated forest road. After a couple of switchbacks, the path will enter the forest on your left. The forest is absolutely beautiful, with a wonderful mountain stream and not a single cedar tree in sight. You’ll have to cross the river 4 times, so use caution if the water level is up. There are plenty of rocks to help you across, so you won’t need to get your feet wet. The trail is well marked with bright blue tape hanging from the trees. These were put up quite recently to replace the worn out red ones, and sometimes you’ll see 2 different paths (the older red one and newer blue one). You can follow either as they lead to the same place. There’s lots of bamboo grass for the first 1.5 km or so, and it can get quite overgrown, so your legs will get soaked if there’s any morning dew on the leaves. The trail basically follows the gully up to the ridge line. When I say follow, I mean just that, as there are very few switchbacks. Someone must’ve had a wicked sense of humor to build such an insane track. The water from the stream seems safe to drink, but you might want to bring a water filter just in case. Continue climbing straight up the mountain. The water will trickle out before disappearing all together, and you’re faced with one of the steepest climbs I’ve ever seen! I’m not sure how you’d make it up in muddy weather, so pray that the ground is solid when you go. There are plenty of ropes to help you, and lots of tree roots to grab/stand on. Luckily, the steep climb is pretty short and you’ll meet up with the main ridge after about 10 minutes. Turn left once you do so, and you’ll start the summit ascent. It should take about an hour to reach the top, and the path isn’t too bad considering what you’ve been through. If the weather is good then you’ll have amazing views of the surrounding peaks (including Mt. Fuji). It was completely covered in cloud when I went, but you can click here to get an idea of what fair weather will bring. According to the map, it should take 3 hours to reach the summit, but considering it’s only 3km from the trailhead to the top, it’s a very conservative estimate. Retrace your steps back to the junction, and consider following the ridge to the top of Mt. Nokogiri (鋸山) for nice views of the mountain you just climbed. You can actually descend via this route (the traditional approach to Mt. Sukai), but you’ve got to scale 12 different peaks using chains and ladders just to get over to Mt. Koushin (庚申山). This could be an alternative route for those relying on public transport (access is via the Watarase keikou railway – わたらせ渓谷鉄道). Bear in mind that it’s a 23km round-trip hike if you choose this approach.

When to go: This hike can be done from mid April to late November, when most of the snow is gone. If coming by car, double check to make sure the forest road is open by calling 0278-56-2111 in Japanese. The name of the forest road is Kurikawa Rindo (栗川林道) and you’ll want to ask if the road is accessible to Sukaibashi (皇海橋).

Access: The start of the track is at the end of a very long and bumpy forest road that is frequently closed because of rock fall. A 4-wheel drive vehicle is recommended for the 1 hour drive. Alternately, you can access the trailhead with a mountain bike. Take a bus from bus stop #1 of Numata (沼田) station and get off at Fukuwari no taki (吹割の滝). The bus takes about 50 minutes and costs around 1300 yen. From there, it’s a 20km bike ride on a very rough road. Click here for the bus schedule. On the web site, click on the 路線バス tab and then select 老神温泉,片品, 尾瀬. All buses on the route stop at Fukuwari waterfall. Most taxis will not take you to the trailhead because of the roughness of the road.

Level of difficulty: 3 out of 5 (elevation change 794m).

Explore posts in the same categories: Gunma hikes (群馬県)

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12 Comments on “Mt. Sukai (皇海山)”

  1. Julian Says:

    Great to hear you made it to Sukai as planned and got up the steep muddy path. Did you rent a car or use a MTB?

  2. wesu Says:

    i don’t have a license, so I brought along a folding bike. it wasn’t the best choice, but I made it (it’s a long story that I’ll eventually chronicle in The Tozan Tales)

  3. Julian Says:

    A folding bike? Amazing you survived, but did the bike? I look forward to your Tozan Tales write-up of that!

  4. Darrell Says:

    Finally checked this mountain off the list as the difficulty of access always deterred me. A few notes of update!
    As a testament to the growing popularity of the hyakumeizan, the LONG 1-hour drive on the forest road to the trailhead is now partially paved, since Wes climbed it 4 years ago! Only some sections of the road is paved, however when I was there, construction was still in the works to continue the paving process. As a result, I saw a few taxis dropping off hikers at the trailhead, so that is now an option from Numata station. I was still surprised by the roughness of the road, and a 4×4 would definitely be ideal. I drove a small Nissan March and I also saw a few kei cars who made the journey, but in my opinion they were driving irresponsibly fast on the mountain road. They were probably rental cars so they didn’t care. I took it slow so as not to damage my undercarriage and suspension. If you are driving, this webpage is very helpful, as it’s quite tricky to find the entrance to the forest road even by car:
    The hike itself is very short, approx. 2.5 hours to the summit, and 1.5 hours on the descent. The forest is very beautiful, but the disappointment was the summit. The summit is very forested, so the views are somewhat obstructed. It reminded me of Amagi-san.
    Still a great hike, but if you’re not climbing the hyakumeizan, consider passing on this mountain, as the long mountain road drive was truly a pain in the butt. The partially paved road is still only 1-way, so be prepared to drive in reverse to the next pullout.

    • wes Says:


      Many thanks for the update. Yeah, I guess it’s about time they paved that horrible road, though they should really consider widening it if they want to attract more hikers.

      I couldn’t tell if there were any views from the summit, as it was foggy up there when I went. I guess winter is the only time you’d get a view since there wouldn’t be any foliage on the trees.



  5. lantzgs Says:

    Thanks for all the info on the post and the comments, it was very useful to find the hiking trail.

    I just climbed sukaisan today so i thought I would share the current conditions. The road is still mostly unpaved. There are two stretches of paved road at the beginning (with unpaved road in between) but the last 11km or so are unpaved.

    If you are planning to cycle, as I did, make sure you take the bus around 7AM from Numata, 8AM (arriving around 9 to the waterfalls bus stop) was too late for me and the sunset caught me cycling back (I spent one hour at the falls before starting in the morning but even if you don’t go to the falls starting at 9AM is quite tight considering the road conditions. Cycling in a pich dark gravel road with monkeys making weird noises and thinking
    about the bear signs was not fun. On top of that my wheel punctured as I was riding hard to use the last rays of light and I dared not stop to fix it with only the bycicle light in the middle of nowhere :-)

    Note: there is no SoftBank coverage at any point during this route even on most of the forest road.

    I hope the info helps other hikers planning this route.

    • David Says:

      Iantzgs – yes I was wondering about the current state of the road and the what the timing should be if going by bicycle. Very useful information indeed.

      • lantzgs Says:

        Sorry for the late reply, I had not checked wordpress comments for a while.

        Mostly a dirt road with a few paved areas. I do not know if I was in bad shape as I do not usually cycle (only hike) but it seemed hard to me, not because of the slope that is not hard, but the wheel getting stuck on the sand.

        As for the timing, if you mean the time of year, any time that there is no snow would be fine. Between late may/early december. But I would not try to climb the steep path mentioned on the main post on a rainy day or the day after.

  6. phydi3kids Says:

    Summited Sukai san this week. It had been dry for quite a while so we made it up the steep section without trouble. Do expect to get your boots wet though if you climb in May due to the snow melt coming down the trail/river. IF I go here again I definitely would like to climb Mt. Nokogiri (鋸山) as there is not much of a view from the summit of Sukai but there are pretty lookouts along the trail. Crazy drive to the trailhead. I was not expecting to see any other hikers on a weekday but was very surprised to find 5 other cars in the lot after the long drive.

  7. David Says:

    I went up Mt Sukai yesterday. After considering all the options, I finally decided to also use my folding bicycle to get to the start of the trail (despite holding a Japanese driving license) since it was the cheapest, least time-consuming and least stressful one. I left my place at 5h30, reached the waterfalls at 9h20 and started out on my bike about ten minutes later. It took me nearly 3 hours to get to the trail head, slightly longer than I had bargained for.

    The first third of the route is mostly paved and it is fairly smooth going. There is a some sort of farm at the end. I could cycle all the way. The middle section is by far the toughest – mostly uphill, hugging a cliff and following what can be barely be described as a road. Most times I just got off my bike and pushed it up. This part felt really really long, and also going down since the roughness of the road really limits your speed. The third section starts after the tunnel and is a mix of up and downs with the path alternating between good and bad bits. I could ride the bicycle half the time here. It was with GREAT relief that I finally came upon the parking at the entrance of the Mt Sukai trail. I was surprised to see a couple of minivans and even a small bus!

  8. David Says:

    (continued from above) I finally started up the trail at 12h40 and got back down at 17h30 after climbing both Sukai and Nokogiri. Although there is a steep tough bit up a (mostly) dry rocky river bed close to the ridge, the first part along the river was truly wonderful.

    The return was easier than expected and I rarely needed to get off and push my bicycle. Despite that, I took 2 full hours to get back and I barely managed to catch the 7h30 bus which allowed me to get the last (non-shinkansen) train back, arriving home a little after 11h30.

    Iantzgs’ warning about time is quite reasonable, however there is 1h30 more sunlight in June so I made it back just as night was falling and without puncturing a tire! my poor folding bike suffered a lot…

    I didn’t see any bear signs but instead I saw 3 actual bears (a mother and 2 cubs) crossing the paved road 20 meters ahead of me while I was on my way up. I also spotted a kamoshika just before that in the trees above the road (and nearly cycled right off it as a result). If I had gotten back earlier I would have bought a lottery ticket.

  9. Hamish Says:

    Since the last update there’s been a heavy typhoon that wiped out part of the road that everyone was using to get there, now the only way to get up Sukai is from the Nikko side (Ginzandaira). It takes a LOT longer than the Sukai Bridge route, at around 10-13 hours round trip

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