Tenno-iwa: Chert Sport Climbing on Tokyo's Akikawa, Mostly 5.10–5.11, No Parking Nearby | Japan Climbing Crags

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Tenno-iwa (天王岩, てんのういわ; listed on Mountain Project as Tennoiwa/ Emperor Rock) sits in Yozawa, Akiruno, in western Tokyo. CLIMBING-net files it under the Akikawa area, and the wall stands right by the road. The rock is chert (チャート), the climbing is bolted sport, and most routes fall in the 5.10s and 5.11s. A short approach makes it a popular crag for beginner-to-intermediate climbers near Tokyo.

The real constraint is parking. Since October 2019 the lot of the Akikawa International Trout Fishing Ground (秋川国際マス釣場) across the road has been closed to climbers, and the road shoulders around it are off limits too. The JFA states plainly: "現状周辺に駐車可能な場所はない" (there is currently nowhere nearby to park). The bus is the simple option. Drivers have to park at Juriki, about 1.7 km away, and walk or ride the bus from there.

What kind of crag it is

CLIMBING-net sums it up: "5.10、5.11台のルートが多く、アプローチの便利さもあって、初中級者に人気がある" (lots of 5.10 and 5.11 routes, and with the convenient approach it is popular with beginner and intermediate climbers).

Route count and grades (checked 2026-10-12)

The three sites give different numbers:

• CLIMBING-net: 46 routes. Up to 5.9: 11; 5.10s: 12; 5.11s: 20; 5.12s: 3.
• ROCKTOPO: 52 entries — 45 face, 1 crack, and 6 boulder problems. Face routes break down as 5.2+: 10, 5.10a+: 12, 5.11a+: 20, 5.12a+: 3. Boulders run from 1-dan to 4-dan.
• Mountain Project: the description says "about 50 routes ranging from 5.7 to 5.12", but only 12 routes are actually entered on the site.

ROCKTOPO splits the crag into three sectors:

Who it suits: the core is 5.10–5.11 and the hardest routes stop in the 5.12s; CLIMBING-net tags it "初心者・中級者OK" (fine for beginners and intermediates). If you're after a long-term 5.12+ project, there's very little here. The lower crag is mostly E-graded, which suits climbers new to leading outside.

When to go

Putting that together:

• People climb here all year. The wall faces northwest and gets little winter sun; CLIMBING-net says outright that winter is cold.
• Summer: Mountain Project recommends it for summer because of the tree shade.
• After rain: those same low, dense trees mean it takes a couple of days to dry, per Mountain Project. After several days of rain, expect wet rock.
• ROCKTOPO's bar chart counts logs uploaded by users. It shows when people tend to go, not an official recommended season.

Getting there

Public transport (recommended)

1. Take JR to Musashi-Itsukaichi Station (武蔵五日市駅), the end of the Itsukaichi Line. Mountain Project describes it as the Chuo Line to the Itsukaichi Line.
2. From stop 1 (1番のりば) in front of the station, take a Nishi Tokyo Bus bound for Kami-Yozawa (上養沢). According to the Nishi Tokyo Bus stop guide for Musashi-Itsukaichi Station, both route 五15 (via Juriki and Sorigo-bashi) and route 檜52 (via Juriki, Akikawa Keikoku Seoto-no-Yu, and Sorigo-bashi) stop at Sorigo-bashi. Akiruno City's access page also lists "≪徳雲院・養沢方面≫ 1番のりば：上養沢行き".
3. Get off at Sorigo-bashi (曽利郷橋), per CLIMBING-net. None of the sources checked give the walking time from the stop to the crag.

None of these pages list departure times or frequency. Check the Kami-Yozawa timetable on Nishi Tokyo Bus before you go.

Driving

• There is no parking near the crag that climbers may use (details in the next section). CLIMBING-net's access note reads "周辺に駐車できる場所はないので、車の利用は控えること" (there is nowhere to park nearby, so avoid coming by car).
• What you can use is parking at Juriki (十里木), about 1.7 km from the crag according to CLIMBING-net, which has both free and paid lots ("無料・有料の駐車場"). Walking from there takes about 30 minutes.
• The two sources disagree on how big the free Juriki lot is. ROCKTOPO's parking page says "about 5 cars" and adds "混雑時は有料駐車場を使用すること" (use the paid lot when it's busy). Akiruno City lists "十里木駐車場" as "駐車台数：約20台・料金：無料・事前予約：不可" (about 20 cars, free, no reservations), with the entrance "十里木交差点で養沢方面へ、左手に見える山小屋風のトイレの手前側" (turn toward Yozawa at the Juriki intersection; the entrance is just before the cabin-style toilet on the left).
• Bus from Juriki: CLIMBING-net says the Ochiai-bashi (落合橋) stop is about 2 minutes' walk from the lot, and the ride to Sorigo-bashi takes about 5 minutes. ROCKTOPO's parking page instead names the nearby stop as "曾利郷橋", about 5 minutes by bus to the stop by the crag. The two sites disagree on the name of the stop next to the lot; go by the sign on site.
• Expressway exit and driving time: none of the crag sources checked give these. Route to the Juriki intersection (十里木交差点) with your own navigation.

Rules to know before you go

Almost every rule at Tenno-iwa concerns parking and toilets. The JFA files it under "駐車場利用禁止・チョーク跡注意" (parking prohibited; watch your chalk marks).

• The trout-fishing lot across the road is closed to climbers. The JFA says that after repeated trouble — "一部のクライマーによる駐車料金の未払い、規定の利用時間を過ぎても駐車場に戻らない" (some climbers not paying the parking fee, and not returning to the lot by closing time) — "2019年10月に、エリア向かいにある『秋川国際マス釣場』のクライマー利用ができなくなる" (from October 2019, climbers could no longer use the Akikawa International Trout Fishing Ground opposite the crag). The banner on ROCKTOPO also says the lot is "クライマーのマナー違反により利用禁止" (closed because of climbers' bad manners).
• No parking on shoulders or open ground either. The JFA writes "周辺の路肩や空き地などへの駐車も厳禁" (parking on nearby road shoulders or vacant land is strictly prohibited). CLIMBING-net adds that the roadsides belong to the fishing ground, and that the fertilizer company managing the materials yard above the crag has also banned parking around it.
• The crag itself could be lost. The JFA warns "このまま駐車や岩場利用マナーの悪化が進めば岩場そのものの利用もできなくなる可能性もある" (if parking and crag manners keep getting worse, the crag itself may become off limits).
• Toilets. ROCKTOPO's banner says "トイレの利用等も禁止" (using the toilets is also prohibited). CLIMBING-net says the toilets at the lot "クライマーの利用をお断りされている" (are closed to climbers): go beforehand and bring a portable toilet (携帯トイレ). If you really must use one, buy something at the fishing ground's restaurant or shop and ask first. Mountain Project also notes that as of 2026 the bathroom is not permitted and that in an emergency you must ask the parking attendants.
• Keep the noise down. ROCKTOPO's banner: "付近で騒ぐ事…も禁止です" (making noise nearby is prohibited).
• Approach path. CLIMBING-net says the landowner has asked climbers not to use the road leading to the former crematorium site; approach via the trail beside Sorigo-bashi on the road below.
• Chalk. The JFA label includes "チョーク跡注意" (watch your chalk marks). Brush off obvious tick marks and chalk when you're done.
• Check again before you go. CLIMBING-net: "登攀禁止も含め、状況が変化する可能性があるので、利用する場合は事前に JFA HP などに目を通すことをおすすめする" (the situation, including possible climbing bans, may change, so check the JFA website before you go).

Registration and fees: the CLIMBING-net, ROCKTOPO, and JFA pages don't mention any registration or access fee.

Notable routes

ROCKTOPO's popular routes (Tenno-iwa page, 2026-10-12):

• クラックジョイ (Crack Joy, 5.9): upper crag, classed as a crack on ROCKTOPO. It's also the only route on Mountain Project's classics list (Crack Joy, 5.9, marked Sport).
• ノーリー (5.10c): lower crag.
• ドロボーカササギ (5.11a): upper crag.

User logs on ROCKTOPO's Tenno-iwa page also mention upper-crag routes such as 涅槃の風, カイーノ, 八月革命, 始祖鳥, 蝉時雨 and ニルバーナ; check ROCKTOPO's route list for their grades.

Where to look things up

• ROCKTOPO: Tenno-iwa: route lists for the three sectors, grade distribution, popular routes, user logs and videos, plus the latest notice at the top. Offline download requires a login.
• ROCKTOPO: Juriki parking: parking notes and directions ("駐車場への行き方を見る").
• CLIMBING-net: Tenno-iwa: Yama-Kei's crag entry, with route-count breakdown, parking and toilet rules, and nearby campsites (神ノ戸キャンプ場, 小岩キャンプ場); its "掲載書籍" (featured in) field lists "関東".
• JFA access-issue list: background on the parking ban; check for new restrictions before you go.
• Mountain Project: English overview, with parking and toilet notes updated in 2026; few routes entered.
• Nishi Tokyo Bus: timetables for the Kami-Yozawa route.

References

• ROCKTOPO: Tenno-iwa (in Japanese)
• ROCKTOPO: Juriki parking (in Japanese)
• CLIMBING-net: Tenno-iwa (in Japanese)
• Japan Free Climbing Association (JFA): nationwide access-issue areas (in Japanese)
• Mountain Project: Tennoiwa/ Emperor Rock
• Nishi Tokyo Bus: Musashi-Itsukaichi Station stop guide (in Japanese)
• Akiruno City: Access to Akikawa Valley (in Japanese)