A small archaeological site stands quietly in Mizue, Funao-cho, Kurashiki City.
This is the remains of a mid-Edo-period structure: the sluice gate of a lock canal, the Ichinokuchi Sluice Gate.
In an era when water transport was the main means of moving goods, it played an important role as the starting point of the canal “Takase-doshi”, which ran through reclaimed land and connected to Tamashima Port.
We visited the Ichinokuchi Sluice Gate, one of the constituent cultural properties of the Japan Heritage story “A Kurashiki story beginning with a single cotton flower: A textile town woven from Japanese and Western influences,” and also designated a historic site of Kurashiki City.
The information presented here is current as of the article’s publication in October 2025. Please note that it may differ from current information.
What is the Ichinokuchi Sluice Gate?
The Ichinokuchi Sluice Gate is a stone sluice gate built in 1645 (Shoho 2) on the right bank of the Takahashi River in present-day Mizue, Funao-cho, Kurashiki City, when Mizunoya Katsutaka, lord of the Bitchu-Matsuyama Domain in the early Edo period, carried out land reclamation and new-field development.
Its dimensions and other details are as follows:
- Type: Lock-type sluice gate
- Height: 7.12 m
- Width: 2.58 m
The Ichinokuchi Sluice Gate, starting point of the “Takase-doshi” canal
Before the land reclamation, the Bitchu-Matsuyama Domain transported goods by boat along the Takahashi River to Tamashima Port, the gateway to the domain.
The subsequent land reclamation expanded the domain’s territory, but boats now had to go out to sea and take a long detour to reach Tamashima Port.
For this reason, a canal was constructed using the irrigation channel from the Ichinokuchi Sluice Gate. Around 1674 (Enpo 2), it became the approximately 9-kilometer lock canal “Takase-doshi”, allowing goods to be transported between the canal and Tamashima Port by Takase boats without going out to sea.
The Ichinokuchi Sluice Gate served as the entrance for Takase boats coming from the Takahashi River, and was used as a canal sluice gate for more than 200 years.
It was later modified during the Takahashi River improvement works of 1925 (Taisho 14), ending its role as a sluice gate, but the Takase-doshi canal remains today.
What is a “lock canal”?
A lock canal is a canal system that uses two sluice gates to adjust the water level and allow boats to pass. The Ichinokuchi Sluice Gate is a lock that adjusts the water level between the canal and the Takahashi River.
It is said that a second sluice gate was built about 300 meters downstream from the Ichinokuchi Sluice Gate, and that water was stored between the two gates to let Takase boats pass.
It is considered one of Japan’s oldest lock canals, built more than 200 years before the famous Panama Canal, which opened in 1914. This attests to the high level of engineering at the time.
What was transported by Takase boats?
Takase boats reportedly carried agricultural products from northern Bitchu downstream, and marine products upstream.
Later, toward the end of the Edo period, specialty products of the Matsuyama Domain, such as iron and tobacco from northern Bitchu, were shipped nationwide from Tamashima Port via Takase boats, supporting the economy of northern Bitchu.
Historical significance
Some Takase boats traveling along the Takase-doshi are said to have carried 50 koku. At approximately 150 kg per koku, some boats are thought to have transported cargo equivalent to that of a 7.5-ton truck.
Although this canal now looks like little more than an irrigation channel, at the time it was a major artery for goods distribution, supporting the region.
The Ichinokuchi Sluice Gate, at the canal’s starting point, retains traces of measures taken to adjust the water level when boats entered the canal from the Takahashi River. Together with Tamashima Port, the endpoint of the Takase-doshi, it is a cultural property of value to the Japan Heritage story and indispensable to Tamashima’s history.
In December 2005, it was also designated a historic site of Kurashiki City.
The Ichinokuchi Sluice Gate today
The Ichinokuchi Sluice Gate ended its role as a sluice gate during the Takahashi River improvement works of 1925 (Taisho 14). In other words, its function as a sluice gate is now only apparent.
Some may wonder why water still flows through it and why it continues to function as an irrigation channel. In fact, agricultural water is supplied from the Takahashigawa Tozai Yosui Association’s water intake and distribution facilities in Sakazu, Kurashiki City, and the channel is still used as the “West Bank Irrigation Channel.”
From left: West Bank Irrigation Channel, West Irrigation Channel, South Irrigation Channel, Bizenhi Irrigation Channel, Kurashiki Irrigation Channel
As the map below shows, a water distribution pipe runs beneath the Takahashi River. The point where it crosses the river and reaches the starting point on the west side of the Takahashi River is where the Ichinokuchi Sluice Gate is located.
《Quoted from “Takahashigawa Tozai Yosui Association: A Century of Progress”》
Water is drawn in by siphon from the location of the Ichinokuchi Sluice Gate, and the channel still extends to Tamashima Port.
From the Writer
The stone sluice gate, about 7 meters tall, standing in Mizue, Funao, Kurashiki City, reflects the outstanding civil engineering skills, wisdom, and ingenuity of the Japanese people.
Ichinokuchi Sluice Gate, the starting point of Takase-doshi, stands as a living witness to history, conveying the achievements of those who came before us to the present day.
Articles about Japan Heritage in Kurashiki City
Ichinokuchi Sluice Gate Information
| Name | Ichinokuchi Sluice Gate |
|---|---|
| Address | Mizue, Funao-cho, Kurashiki City, Okayama Prefecture |
| Contact | None |
| Website | Kurashiki City Official Website (Ichinokuchi Sluice Gate) |
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