Miyauchi Family Residence Tide-Viewing Basin

A Tide Gauge Inside a Merchant's Garden

The Miyauchi Family Residence Tide-Viewing Basin (宮内家住宅潮見堀, Shiomibori) is a late-Edo stone structure within the Miyauchi Family Residence in Nadamachi, Iyo City, Ehime Prefecture, listed as a Registered Tangible Cultural Property on 10 May 2018. It is a trapezoidal pit about 1.5 meters deep covering 8.7 square meters. The Agency for Cultural Affairs dates it to the late Edo period, between 1751 and 1830.

The name says what it did. Water connected to the sea was drawn into the grounds, and the rise and fall inside the pit told the household what the tide outside was doing. Ships could only work the harbour on the right tide, and the family could take that reading without stepping outside the compound.

The Miyauchi family had come to this shore in 1636 from the village of Kaminada, founded the town of Nadamachi, and served as town elders while brewing sake and trading Ozu washi paper. Their income moved with the shipping, and the Miyauchi Family Residence Tide-Viewing Basin is what that dependence looks like built in stone.

Listed as Hard to Reproduce

Of the four items registered here on the same day, only the Miyauchi Family Residence Tide-Viewing Basin was entered under the criterion for structures that would be difficult to reproduce. The main house and the old retirement house were listed for their contribution to the historic landscape, the retirement house as a model of design.

The reason is the function. Tide-measuring stations became standard infrastructure in the modern period, run by government offices at working harbours. A private household keeping its own tide gauge in the garden during the Edo period has almost no parallel, and the Ehime Prefectural Board of Education calls it a rare example of such a facility inside a dwelling.

Even the counting unit differs. The three roofed buildings are recorded as one mune each, the unit for buildings; the Miyauchi Family Residence Tide-Viewing Basin is recorded as one ki, the unit used for constructed works that are not buildings.

How the Stonework Is Made

The basin lies on the harbour side of the compound, west of the old retirement house. Its plan is a trapezoid, and stone steps run down into it from the west so that someone could descend to the waterline and read the level directly.

The walls are built of chlorite schist. Flat, slightly rounded pieces are laid in level courses, with larger blocks worked in at intervals to break the rhythm. Chlorite schist splits into thin plates and occurs widely across the Iyo region, which makes it well suited to this kind of flat coursing. Since tidal water keeps the stone permanently wet, the choice of material decided how long the structure would last.

Iyo City's tourism office notes that the same masonry technique appears in the Sazae-bori at Goshikihama, a well built when the Ban'an harbour was laid out in 1812, with its stones stacked in a spiral like a staircase. The stonework of the Miyauchi Family Residence Tide-Viewing Basin most likely comes out of the same body of harbour-building skill.

Getting There, and What Is Closed

The Miyauchi Family Residence Tide-Viewing Basin is closed to visitors. The compound is still a family home and access stops at the main house on the street. The basin lies deeper in, on the harbour side, and there is no point on the road from which it can be seen.

The main house has been repaired and operates as the Musee Nadaya community space, rented by advance booking in blocks between 8:00 a.m. and 11:00 p.m. The dedicated line is 080-2981-6281, and that is the number for any question about the rear of the compound, including the Miyauchi Family Residence Tide-Viewing Basin.

Photography does not apply, as the structure is closed and out of sight. Please treat the site as a private home.

Nadamachi is about three minutes on foot from Iyo Station on the JR Yosan Line or Gunchuko Station on the Iyotetsu Gunchu Line. The Sazae-bori well at Goshikihama, said to use the same coursing, is open and can be visited freely. Fifteen free parking spaces are shared between the lot behind the main house and the Eiyoji temple lot.