Mizugakiyama: Granite Cracks, Multi-Pitch and Highballs Behind a Winter Road Closure | Japan Climbing Crags

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Mizugakiyama (瑞牆山, みずがきやま) sits in Sutama-cho Ōmi, Hokuto City, Yamanashi, in the Okuchichibu range. It is a granite area built around crack climbing and multi-pitch, with a large field of boulders in the forest below. Two questions decide whether it suits you: can you place your own gear on cracks, and will the forest road be open when you go?

What kind of crag is it

Rock and terrain: both ROCKTOPO and CLIMBING-net list the rock as granite (花崗岩). Hokuto City's spot page is more specific: "全山が黒雲母花崗岩で形成され" — the whole mountain is biotite granite (Hokuto City). CLIMBING-net gives wall angles of "80~100度", so mostly vertical.

Size (checked 2026-10-12):

Grade spread (ROCKTOPO): cracks cluster in the 5.10s (143 routes from 5.10a), with another 96 at 5.9 and below. Face routes peak in the 5.11s (93). There are still 59 cracks at 5.12a or harder, and two 5.14s each in crack, face and multi-pitch. Of the 539 boulder problems, the largest band is 4-kyu and up (180), and 131 are shodan or harder.

History: CLIMBING-net traces development to the 1970 first ascent of Ōyasuri-iwa (大ヤスリ岩) by the Tokyo High Peak Club. In 1981 Naoki Toda freed the first pitch of "Haru Urara" (春うらら) on the Jūichimen-iwa toe at 5.11b, and in 1984 the second pitch at 5.12a, one of the hardest routes of the time. Kasameri-sawa (カサメリ沢) was developed as a sport area in 1989. CLIMBING-net also notes that bolt-free trad development has been revived in recent years ("ボルトを使わないトラッド志向のルート開拓が見直され"), so the area leans trad.

Who it suits: climbers who can lead 5.9–5.10 cracks on gear and have multi-pitch experience get the most out of it. Sport-only climbers should look at Kasameri-sawa / lower Fudō-sawa, the subarea with the most face routes on ROCKTOPO (162). Boulderers head to Mizugakiyama Boulder. Mountain Project sums it up as "Known for it's highball bouldering and longer trad lines" (MP), so bring enough pads and spotters for the highballs.

When to go

The winter closure has two published end dates:

• CLIMBING-net: "冬季（12月上旬～4月中旬）は閉鎖。利用は可能だが、ゲートが閉まるため車での乗り入れはできない" — closed early December to mid-April; you can still walk in, but the gate is shut to cars.
• Hokuto City (nature park office): closed "冬期12月上旬～4月下旬　※県営林道　みずがき線の冬季閉鎖による" — early December to late April, because the prefectural Mizugaki forest road closes (Hokuto City). japanesealps.net also says "冬期(12月上旬～4月下旬)は県営林道みずがき線が閉鎖".

The Yamanashi forest-road status page for the Mizugaki line lists winter closure (冬期閉鎖) as a restriction type but gives no dates. If you plan to drive in during early or mid April, check that page or call the Chūhoku forestry office number listed on it. The prefecture's general notes add that roads also close after heavy rain (50 mm or more of continuous rainfall) or an earthquake of shindo 5-lower or above (Yamanashi).

Drying and humidity: ROCKTOPO's subarea notes show how much altitude matters. The Epsilon area "標高が高いため、春は地中の氷の層からの給水が続き、夏は結露、秋も遅くならないと乾かない" — spring seepage from frozen ground, summer condensation, dry only in late autumn. By contrast, the upper tier of Hagoromo-iwa "南面で露出しており、雨の後でも乾きが非常に早い" — south-facing and quick to dry after rain (RT). ROCKTOPO also keeps a list of routes on Ogawayama and Mizugaki that can be climbed in the rain (小川山・瑞牆で雨でも登れるルート).

Mountain Project says "If you do not mind near freezing temps December is great friction", but read that alongside the closure: from early December the gate is shut and you cannot drive to the nature park.

Getting there

Public transport: a seasonal bus, the Nirasaki–Mizugaki line (韮崎瑞牆線, nicknamed the Mizugaki Route), runs from JR Nirasaki Station on the Chūō Main Line to Mizugaki Sansō (みずがき山荘), operated by Kayagatake Mizugaki Den'en Bus (operator timetable page).

• The operating period is announced each year; for fiscal 2026 it was "令和8年4月4日（土）～11月23日（月）" (April 4 to November 23, 2026).
• There are separate weekday, weekend/holiday and special-weekday timetables, and some runs are "土曜・休日のみ運行。（平日運休）" — weekends and holidays only.
• Buses can be cancelled at short notice for typhoons; the operator posts updates on its homepage and X.

The bus does not reach Mizugakiyama Nature Park, where most climbers start. japanesealps.net: "季節運行される登山バスは瑞牆山荘までなので、みずがき山自然公園へはマイカーかタクシーとなります" — the bus stops at Mizugaki Sansō, so the park means a car or taxi. I found no primary source for the walking distance or time from Mizugaki Sansō to the park. japanesealps.net lists three taxi companies (Kai Taxi, Asahi Taxi, Nirasaki Taxi) under access to the Mizugaki Sansō trailhead, and the bus operator's page links to a hiker taxi service (Sankyō Taxi).

Driving: CLIMBING-net's directions: leave the Chūō Expressway at Sutama IC (須玉IC), head toward Masutomi, pass Shiokawa Dam, turn right at the Kuromori settlement, go about 1 km, carry straight on rather than toward Green Lodge, then turn left to reach the former tree-planting festival grounds (植樹祭跡地), i.e. the nature park. I found no primary source for the driving time.

Parking:

Hokuto City, CLIMBING-net and japanesealps.net all put the main lot around 100 cars; ROCKTOPO's figure of about 20 is far lower, for reasons not stated. CLIMBING-net asks climbers, who stay longer than other visitors, to park at the ends of the lot in busy seasons, and suggests carpooling from the main lot because the road-end spaces are limited. ROCKTOPO's parking page adds "連休時などは混雑します" — it gets crowded on long weekends. japanesealps.net marks the nature park lot as free (無料駐車場).

Rules to know before you go

• No parking at the gate: ROCKTOPO's banner reads "ゲート前は駐車禁止です。（冬も工事車両が通ります）" — construction vehicles use it even in winter. The boulder page adds "トポで駐車禁止の場所に駐車しないように。酷い路肩駐車も目立ちます" — don't park where the topo says not to; bad roadside parking is common (RT 241).
• Closed boulders: within Mizugaki Boulder, Akanezumi-iwa (赤鼠岩) and Nana-iwa (七岩) are on land managed by Mizugakiyama Mori no Nōen campground and are closed to climbing; non-guests may not enter at all, on foot or by car (JFA).
• Camping: tents only at the designated campground; no tents, cooking or eating outside your car in the nature park lot; pitch on the lawn around the office, and "植樹広場（上の段の芝生）は幕営禁止" — no camping on the upper lawn. Fees differ by source: CLIMBING-net says "クライマーは一張り1日1000円" (¥1,000 per tent per day for climbers), while the Hokuto Tourism Association lists "1人 1500円、2～4人 3000円、5人以上 4000円" (¥1,500 solo, ¥3,000 for 2–4, ¥4,000 for 5+); confirm on site (CN, Hokuto Tourism Association). Hokuto City says reservations are not accepted ("予約　不可") and the office closes on Wednesdays (Hokuto City).
• Fire and rubbish: no open fires on the ground — use a fire stand or stove; carry out all rubbish; the electric fence is live at night (CN).
• National park: Mizugaki is inside Chichibu-Tama-Kai National Park, and CLIMBING-net states that excessive cleaning, cutting trees or altering the ground ("必要以上に掃除したり、木を切ったり、下地を変えたり") is not allowed.
• Water intake: the stream beside "Moeta Chizu" (燃えた地図) feeds the Healthy Land campground below; stay away from it and don't trample the area (CN).
• Toilets: CLIMBING-net's public toilet field says "無" (none), while the Hokuto Tourism Association lists one toilet at the nature park. The two disagree.

Notable areas and routes

Main walls (CLIMBING-net): Jūichimen-iwa (十一面岩, toe and main face), Kanmanboron (カンマンボロン), Ōmen-iwa (大面岩), and the sport area Kasameri-sawa. Approaches: 30–40 minutes ("30~40分") from the nature park lot to the Jūichimen-iwa toe, then another 20–30 minutes to the main face; Kanmanboron is about 30 minutes from its parking ("駐車場から30分ほど"), with Ōmen-iwa another 10 minutes. From the main face you can rappel along "Haru Ichiban", "肩から50m×4回" — four 50 m rappels from the shoulder.

ROCKTOPO subareas (route counts):

ROCKTOPO popular routes (人気の課題): よろめきクラック (5.10a), レーザーズエッジ (5.10c), 真実の口 (5.11a), 金のわらじ (5.12a), トップガン (5.13a).

Mizugakiyama Boulder: ROCKTOPO splits it into 7 subareas; the largest are 植樹祭エリア付近 (191 problems) and ハットエリア (125). Popular problems include あかね雲 (3-kyu), 指人形 (shodan) and 千里眼 (nidan) (RT 241). Hokuto City describes the "3～5mの岩" (3–5 m rocks) scattered through the woods as popular with boulderers.

Where to look things up

• ROCKTOPO Mizugakiyama and Mizugakiyama Boulder: route lists, grade spread, subareas, parking pages and banner notices. Topo downloads require a login.
• CLIMBING-net Mizugakiyama: history, approaches, camping rules; the guidebook field lists "伊豆・甲信".
• Hokuto City: Mizugakiyama Nature Park: office closing days, winter closure, phone 0551-45-0277.
• Yamanashi: Mizugaki forest road: current road restrictions.
• Nirasaki–Mizugaki line timetable: this year's operating period and PDF timetables (English versions available).
• JFA access-issue list: closures and cautions.
• Mountain Project Mizugaki Yama: English overview, few routes.

References

• ROCKTOPO: Mizugakiyama (in Japanese)
• ROCKTOPO: Mizugakiyama Boulder (in Japanese)
• ROCKTOPO parking: Mizugakiyama Nature Park lot (in Japanese)
• ROCKTOPO parking: Kasameri / Fudō-sawa spaces (in Japanese)
• CLIMBING-net: Mizugakiyama (in Japanese)
• Hokuto City: Mizugakiyama Nature Park office and campground (in Japanese)
• Hokuto City: Mizugakiyama Nature Park, mountain guide (in Japanese)
• Hokuto Tourism Association: Mizugakiyama Nature Park (in Japanese)
• Yamanashi Prefecture: Mizugaki forest road status (in Japanese)
• Yamanashi Prefecture: forest road notes (in Japanese)
• Kayagatake Mizugaki Den'en Bus: Nirasaki–Mizugaki line timetable (in Japanese)
• japanesealps.net: Mizugakiyama access and parking (in Japanese)
• JFA: nationwide access-issue areas (in Japanese)
• Mountain Project: Mizugaki Yama
• Mountain Project: Yamanashi Prefecture