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Hinokiboramaru Day Hike | The Tsutsuji Shindo Trail from Nishi-Tanzawa in Early Summer

2024.07.02

"I want to climb Mt. Fuji soon, but going straight into the real thing feels risky." That was exactly my situation, and the training hike I chose was Hinokiboramaru (1,601 m), a well-known peak in western Tanzawa, Kanagawa, about two hours from central Tokyo. The climb gains over 1,000 m, which is plenty, and you can still do it out and back in a day. Within Tanzawa, it has real substance.

This post is an honest report of an early-summer day hike from the Nishi-Tanzawa Visitor Center up the Tsutsuji Shindo trail and back. The stream crossing at Gorasawa Deai, the climb that drains your legs, and heat that already felt like midsummer — I've covered the shape of the route, the difficulty, access, and the things specific to Tanzawa you should know about (heat, land leeches, bears).

The short version: Hinokiboramaru is a little hard as a beginner's first step up, but it's excellent as a warm-up before a serious summer mountain. Here's why.

Route summary (day hike, out and back on Tsutsuji Shindo)

• Area: western Tanzawa range (Tanzawa-Oyama Quasi-National Park, Kanagawa)
• Summit: Hinokiboramaru, 1,601 m
• Start/finish: Nishi-Tanzawa Visitor Center
• Route: Nishi-Tanzawa Visitor Center → Gorasawa Deai → Tenbo Enchi viewpoint → Ishidanayama ridge junction → summit, returning the same way
• Distance: about 1.4 km from the trailhead to Gorasawa Deai; a little over 5 km each way to the summit
• Difficulty: 3/5, with the demand mostly on stamina. There isn't much genuinely dangerous rock, but between the stream crossing early on and the long steep climb above the viewpoint, this is a fitness route.

What kind of mountain is Hinokiboramaru?

Hinokiboramaru stands at 1,601 m in the western Tanzawa range, the fourth-highest peak in Tanzawa. The whole area is designated as Tanzawa-Oyama Quasi-National Park — deep forest and clear streams, and a lot of nature for somewhere this close to Tokyo.

The unusual name is said to come from Hinokibora, a stream running off the southeast side of the summit. It also goes by Aogatake, an alternative name. There's something quietly reserved about both the sound of the name and the mountain itself.

The main reason I chose it was that it makes good training for Mt. Fuji. The elevation gain from the visitor center to the summit is substantial, so you get a proper sustained climb. On a clear day you can see Fuji from near the top, which helps get you in the mood for the real thing.

Starting from the Nishi-Tanzawa Visitor Center

We started at the Nishi-Tanzawa Visitor Center, filing our climbing plan and using the toilets before setting off. Just after 8:30 in the morning it was already 27°C and 60% humidity. Sweat started before we'd properly begun — it felt like midsummer, not early summer.

The Tsutsuji Shindo is the standard trail to Hinokiboramaru. It narrows almost immediately. There are sections with unreliable footing, and I remember telling myself to pay attention or I'd go over. Gorasawa Deai is about 1.4 km in — that's the first checkpoint.

Not long after we started, white mist closed in for a while. That particular sensation of the view simply shutting off. It's atmospheric, and it's very much the face Tanzawa wears in summer.

The first obstacle: the crossing at Gorasawa Deai

About an hour in, you start to hear water. I've never quite worked out why the sound of a stream alone makes you feel so much cooler and clearer. The cold air off the water soaked into bodies that were overheating.

We arrived at Gorasawa Deai, where the Tsutsuji Shindo crosses the stream. This is a tricky one — depending on the water level and the state of the stepping stones, every line looks likely to soak your boots. My partner and I talked through the options — "this side looks safer," "no, you'll get wet there too" — and picked our way across carefully.

The crossing is the first place on this route that demands attention. If the water is high, don't force it: waiting for it to drop, or turning back, are both legitimate calls. Take particular care after rain.

Above the viewpoint, it becomes a test of stamina

Past Gorasawa Deai, the climbing starts in earnest. From the Tenbo Enchi viewpoint upward, exactly as I'd been warned, the steep ground simply keeps going.

Combined with the humidity, it takes a lot out of you. About halfway up, the altimeter had only reached the 870 m mark. "Still only halfway" was genuinely deflating, but I took frequent breaks and held my own pace. Once you reach the Ishidanayama ridge junction near the top, you're close.

There's no chain of exposed rock or cliffs, so this is a mountain where you face the plain difficulty of climbing rather than the fear of rock. Which is precisely why it earns its place as Fuji training.

What to watch for in Tanzawa in early summer

Some of these apply to Tanzawa in summer generally, not just Hinokiboramaru. Here's what I was actually thinking about on the day.

Heat and hydration

27°C and 60% humidity from the morning, as we had, is not unusual. Even on low and mid-height mountains, heatstroke risk rises in summer. Carry more water than you think you need, take frequent breaks, and keep your salts up. Synthetic clothing that moves sweat away, and a headband to keep it out of your eyes, make a real difference to how the day feels.

Land leeches

Tanzawa is also known for yamabiru, land leeches, in summer. We were fortunate not to meet any, but after rain or on damp trail you can't be complacent. Carry repellent spray, avoid sitting on wet ground during breaks, and check your feet and legs regularly.

Bears

Tanzawa is bear country, and walking a quiet trail, the thought of an encounter is honestly a little frightening. I bought a new bear bell for this hike — one with a magnet that silences it. Being able to mute it during breaks and in busy places, then let it ring on deserted sections, turned out to be very useful. Letting animals know you're there early feels like the kinder way to walk, for the bears and for you. (For more on whether bells actually work, and on alternatives, see the report from the Omote-One ridge where I tried firecrackers.)

Access and planning

• Public transport: the standard approach is a bus from Shin-Matsuda Station on the Odakyu line to the Nishi-Tanzawa Visitor Center. Services are limited, so check the timetable in both directions before you go.
• By car: exit the Tomei Expressway at Oi-Matsuda IC and follow Route 246. Parking near the visitor center varies with the season and time of day, so arriving early is the safe move.
• Time on the trail: allow three to four hours for the ascent, and build in extra for the crossing and the steep section. Days are long in summer, but starting and finishing early is still the rule.
• Kit: boots with grip for slippery trail and the stream crossing, quick-drying layers you can add and remove easily, plenty of water, and a bear bell. Those four are the ones worth getting right.

Conclusion: an excellent warm-up before the real thing

Coming back from Hinokiboramaru in early summer, what stayed with me is that this is a fitness mountain. Because it isn't a series of dangerous rock sections, the question it asks is whether you can hold your own pace against humidity and a long steep climb.

Which is exactly why I recommend it as preparation for Mt. Fuji or a serious summer mountain. The crossing at Gorasawa Deai gets you used to moving around water; the climb above the viewpoint builds endurance. And you get to experience the practical realities of a Japanese summer mountain — heat management, leeches, bears — all in a single day.

Hinokiboramaru, fourth-highest in Tanzawa, also known as Aogatake. It's a quiet mountain, and a good place to take one step toward a bigger one. Plan conservatively and enjoy it safely.

🛒 See the gear from the video as a list → Staying comfortable on low mountains in summer: heat gear

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