Hirase Water Purification Plant No. 2 Tunnel Upper Portal

A Granite Gate at the Head of the Intake Tunnel

The Hirase Water Purification Plant No. 2 Tunnel Upper Portal (平瀬浄水場第２隧道上口) is a stone conduit portal built in 1913 in Hirasecho, Kofu, Yamanashi Prefecture, and was entered on the national register of Registered Tangible Cultural Properties on August 23, 1999. It marks the upstream entrance of the tunnel that carried raw water from the Arakawa River intake to the Hirase plant.

It belongs to the original construction of 1913, when Kofu first received piped water. The intake conduit ran underground for part of its length and surfaced again inside the plant grounds. The exit is marked by the registered Former Intake Gate; this is its partner at the entrance. Yamanashi Prefecture's heritage list writes the name with the kanji numeral, as Dai-ni Zuidō Kamiguchi.

The gate is modest: 4.3 metres wide and 3.3 metres high. Its counterpart at the plant end is a far grander affair at 14.4 metres wide and 11.0 metres high.

Why It Was Registered

The portal was registered for its contribution to the historic landscape. The Agency for Cultural Affairs describes it as one of the surviving works of Kofu's founding waterworks and singles out the care of the masonry: granite blocks dressed to look like edokiri work, with a narrow smoothed margin cut along every joint.

That finish draws each stone's outline as a crisp line. It is a lot of effort for a doorway that, once the system was running, almost no one would see, and it says something about how seriously the builders took the job.

This was the last of the six Hirase structures to be registered. The Former Intake Gate at the other end of the conduit had been registered in 1998, so the entrance and exit joined the register about a year apart.

The Tablet Above the Door

Above the opening hangs a tablet with four characters, transcribed by the Agency for Cultural Affairs as 挙鍾為雲. The inscription over the Former Intake Gate at the far end is given as 決渠為雨 by the waterworks bureau and as 沢渠為雨 by the Agency.

The pairing appears to borrow from an irrigation song recorded in the Han-dynasty history Hanshu: raise the spade and it becomes cloud; open the channel and it becomes rain. In the original text the character for spade is 臿, not 鍾. If the reading holds, the cloud line was set over the intake end and the rain line over the outlet, so the couplet completes itself across the length of the conduit.

Anyone who gets close should look at three things: the characters on the tablet, the tooled lines along the granite joints, and how small the gate is compared with the grand portal at the plant end. Here the builders signalled importance through stonework rather than size.

Visiting

The Hirase Water Purification Plant No. 2 Tunnel Upper Portal lies outside the plant grounds, somewhere in Hirasecho; no street number has been published. It is not included in the waterworks bureau's plant tours, and there is no announced public access.

Official sources do not say whether the gate can be seen from any public spot. If you want to see it, contact the Water Purification Division of the Kofu City Waterworks and Sewerage Bureau, which owns the structure, before you go. There is no published guidance on photography.