A working brick lock of 1921
The Yokotone Lock Gate (横利根閘門, Yokotone Kōmon) is a brick navigation lock at Nishidai in Inashiki City, Ibaraki Prefecture, completed in 1921 (Taishō 10) and designated an Important Cultural Property in 2000 (Heisei 12).
It stands at the southern end of the Yokotone River, a short distance above the point where that river empties into the Tone River. The prefectural boundary runs through the site, so the car park on one side lies in Chiba Prefecture while the lock itself belongs to Ibaraki.
The Yokotone Lock Gate was built as part of the Tone River improvement scheme carried out directly by the Home Ministry between 1900 (Meiji 33) and 1930 (Shōwa 5). Construction was led by the engineer Nakagawa Kichizō, broke ground in August 1914 (Taishō 3) and reached completion in March 1921. The Yokotone River was then a working artery between Lake Kasumigaura and the Tone River, and a lock was needed because the two waterways sit at different levels, with the difference reversing according to the state of the flood.
The plan is simple to read on the ground. A long chamber, where a boat waits while the water level is adjusted, is closed at each end by a lock head holding the gates. Inashiki City gives the overall dimensions as 90.9 m in length and 10.9 m in width, which made it one of the largest structures of its kind in Japan when it opened.
Why the lock is designated
The Yokotone Lock Gate was designated an Important Cultural Property on 25 May 2000 under two of the national criteria for buildings, technical excellence and high historical value. The Agency for Cultural Affairs describes it as one of the representative civil engineering structures produced by the Tone River improvement works, and as a point of arrival in the history of brick lock construction in Japan.
Two things carry that judgement. The first is material. This was the last lock in Japan to be built in brick and stone, at a moment when concrete was about to take over, and the standard of both design and execution is unusually high. The second is the arrangement of the gates. The Yokotone Lock Gate is a double-chamber lock, and each lock head carries a pair of leaves, one opening inward and one opening outward, so that the structure can hold back water pushing from either direction.
What the designation covers is set out item by item. It takes in the chamber together with the fender timbers along both banks, 2 lock heads including 4 gate leaves, 4 rack bars, 2 sluice gates and 1 gate-operating mechanism, and 4 retaining walls outside the lock. Four further items are listed as Tsuketari, attached to the designation rather than forming part of it: the Tone River flood-control commemorative stele, the site of the bust of Nakagawa Kichizō, sections of the original gate leaves, and the old sluice-gate hoisting machinery.
What to look for on site
Walk along the top of the Yokotone Lock Gate and the brick face reveals its logic. Long recesses are cut into the chamber walls at each end so that the leaves can fold flat against the masonry when a boat passes, and cut stone runs along the coping where the brick would otherwise take the wear. Timber fenders sit at the waterline on both sides, still doing the job of protecting hulls and masonry from each other.
The machinery is a mixture of periods, and the seams are visible. In 1994 (Heisei 6) the Ministry of Land, Infrastructure, Transport and Tourism, then the Ministry of Construction, repaired the most badly weathered fabric and converted the gates to automatic operation. Sections of the original gates and the old hoisting gear were kept and are listed among the attached items, so the replaced parts and the retained ones can be compared.
This is not a preserved ruin. Fishing boats and small pleasure craft still lock through, and if one arrives the whole cycle plays out in front of you: the warning sound, the gates closing, the water in the chamber rising or falling, and the signal turning to let the boat out. Waiting for that to happen is the best reason to linger.
The grounds on both banks were laid out as Yokotone Lock Gate Fureai Park when the refurbishment finished, and opened to the public in 2000. A viewing terrace looks down the length of the chamber towards the Tone River, and the poplars, zelkovas and cherry trees planted here give the place an oddly European air for the lower Tone. The cherries are the local draw in early April.
Visiting the Yokotone Lock Gate
The Yokotone Lock Gate can be seen at any time. The surrounding Yokotone Lock Gate Fureai Park is an open riverside park with no gate and no admission charge, and free parking is provided beside it. There is no visitor centre and no staffed reception, so plan on a self-guided walk of 30 to 40 minutes along both banks.
The nearest railway station is Sawara on the JR Narita Line, about 10 minutes away by car or taxi. There is no direct bus, and the walk along the levee from the station takes the better part of an hour, so a car or taxi is the practical choice. From central Tokyo, allow roughly 2 hours by road.
Photography is unrestricted in the park and on the banks, including tripod work. The one rule that matters is a safety rule rather than a heritage one. The lock is live infrastructure operated by the Ministry of Land, Infrastructure, Transport and Tourism, so keep off the gates and away from the machinery, and stand clear of the chamber edge when a vessel is locking through. Questions about navigation are handled by the Tonegawa Downstream River Office of the Kantō Regional Development Bureau on 0478-52-3795.
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Q&A
- Can I visit the Yokotone Lock Gate, and is there an admission fee?
- Yes. The lock stands inside Yokotone Lock Gate Fureai Park, which is open at all hours with no admission fee and free parking. There are no guided tours and no interior access, since the structure is a working lock rather than a building.
- How do I get to the Yokotone Lock Gate by public transport?
- Take the JR Narita Line to Sawara Station, then a taxi for about 10 minutes. No bus route serves the site directly, and walking from the station takes close to an hour along the river levee.
- Is the Yokotone Lock Gate still in use?
- It is. Fishing boats and small pleasure craft pass through between the Tone River and the Yokotone River, and the gates were converted to automatic operation in 1994. Passage is managed by the Ministry of Land, Infrastructure, Transport and Tourism, and can be suspended after floods.
- Why was the Yokotone Lock Gate designated an Important Cultural Property?
- It was designated in 2000 for technical excellence and high historical value. It is the last brick and stone lock built in Japan, one of the largest of its day, and a double-chamber design with inward and outward opening leaves at each end.
- When is the best season to see the Yokotone Lock Gate?
- Early April, when the cherry trees planted through the park come out against the brickwork. Boat traffic is heaviest in the fishing season from spring to autumn, which improves the chance of seeing the lock operate.
Basic Information
| Name | Yokotone Lock Gate |
|---|---|
| Location | Nishidai, Inashiki City, Ibaraki Prefecture |
| Designation | Important Cultural Property |
| Year Designated | 2000 (Heisei 12), on 25 May |
| Quantity | 1 lock (1所) |
| Dimensions | 90.9 m in length, 10.9 m in width |
| Owner | The State (Ministry of Land, Infrastructure, Transport and Tourism) |
| Public Access | Open at all times as part of Yokotone Lock Gate Fureai Park. No admission fee. Exterior viewing only |
References
- National Cultural Properties Database, Agency for Cultural Affairs: Yokotone Lock Gate
- https://kunishitei.bunka.go.jp/bsys/maindetails/102/3676
- Inashiki City: Yokotone Lock Gate (Nishidai)
- https://www.city.inashiki.lg.jp/page/page000054.html
- Inashiki City: Yokotone Lock Gate Fureai Park
- https://www.city.inashiki.lg.jp/page/page000044.html
- Kantō Regional Development Bureau, Tonegawa Downstream River Office: notice on reopening of the Yokotone Lock Gate
- https://www.ktr.mlit.go.jp/tonege/tonege00787.html
- Ibaraki Prefectural Board of Education: Yokotone Lock Gate
- https://kyoiku.pref.ibaraki.jp/bunkazai/kuni-28/
Last verified: 2026.09.06