Slot Canyon Atlas

Atlas › Tanigawa-renpo (Gunma)

Narumizu-sawa

not verifiedpermit verified 2026-08-20 Ungraded High flood risk Minakami, Gunma

Emerald pools, kilometer-long slabs, and a meadow exit onto the Asahi-dake ridge. The classic Tanigawa overnight sawanobori.

Often paired with East Kurosawa (Higashi-Kurosawa) as the approach drainage, with descent back down East Kurosawa to close the loop. The 'Tokyo kiten sawanobori route 120' guidebook lists this as one of the marquee Tanigawa lines. Parties typically bivy below the upper waterfalls and finish over the ridge the second day. Snowfields linger into June and turn the upper slabs into a postholing slog; mid-July onward is the honest window.

Logistics

ManagerJoshinetsu-kogen NP, Forestry Agency
PermitNo permit is required for this drainage. Gunma Prefectural Police nonetheless ask every party going into the mountains to submit a climbing plan or a climbing card, which is standard practice for sawanobori. Note the regime next door: the Gunma Prefecture Tanigawa-dake Accident Prevention Ordinance designates the Ichinokura-dake south face rock area as a climbing danger zone. From 1 March to 30 November anyone entering it must file a tozan-todoke in duplicate at least 10 days ahead with the Tanigawa-dake Climbing Guidance Center in Yubiso, or submit online through Compass, and the ordinance carries penalties for entering without one. Danger-zone climbing is also banned outright during the spring snowmelt window from late March into late April, and discouraged from 1 December to the end of February. This canyon sits outside that zone, but the boundary is close enough to be worth knowing.
Distance~8 to 10 mi total loop with East Kurosawa approach
Elevation~2,000 ft gain to the Asahi-dake ridge
Time1 to 2 day overnight
TechnicalClassic intermediate sawanobori in the Okutone region. Approach via Higashi-Kurosawa (East Kurosawa), a soothing run of slabs and short waterfalls including Hanage-no-taki climbed on the left. Main line up Narumizu-sawa features emerald plunge pools, long nameshou slabs, an S-curved gorge, and Uodomari-no-taki bypassed right at high flow. Sawanobori grade 2 (intermediate). Exits onto Asahi-dake ridge with a meadow finish (the 'tengoku-no-tsume', heaven's pinch).
SeasonMid-July to early October. Snowmelt persists into late June.
Flood riskHigh. The Tanigawa massif draws heavy thunderstorms; the slot funnels everything off Asahi-dake and Shichikoyayama. Cancel on any forecast rain in the upper drainage.
Vehicle access2WD paved to the Shiraga-mon trailhead via Tochibora Onsen.
CrowdModerate. The most-trafficked overnight sawanobori line on the Gunma side of Tanigawa.
Coordinates36.859, 138.946

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