Tsunekawa Government Office Ruins

A Government Office Beneath the Fields of Zakōji

On a low river terrace in the Zakōji district of Iida, between 420 and 438 metres above sea level, the ground holds the outline of an administrative complex that once ran the affairs of an entire ancient district. Almost nothing of it stands above the surface today. What survives is a pattern of postholes, foundation stones, boundary ditches and charred grain, recovered over more than seventy rounds of excavation. Archaeologists identify the site as the seat of the Ina District government, the kanga that collected taxes, stored grain and recorded the business of southern Shinano Province from the late seventh century into the early tenth. It was designated a National Historic Site in March 2014, and an additional area was added to the designation in October 2016.

The name Gonga itself may carry a memory of that role. Local pronunciation tends toward "Gongawa," and Edo-period land registers wrote the place as "Gokawa," probably after the several springs that once fed small streams here. One long-standing suggestion connects Gonga to gunga or gūke, the old words for a district office, though that reading is far from certain.

What a District Office Was, and How This One Came to Light

Under the ritsuryō system of centralised law that Japan adopted in the seventh and eighth centuries, the country was divided into provinces and, below them, districts. A kanga was a government office. A provincial office was a kokuga, roughly equivalent to a modern prefectural headquarters, and a district office below it was a gunga. The Gonga Kanga Site is the district-level office for Ina, one of the ten districts that made up ancient Shinano.

The first finds came in 1977, when construction of a bypass for National Route 153 cut through the ground at Zakōji. Excavators turned up remains spanning the Jōmon period to early modern times, but the Nara- and Heian-period material drew particular attention: rows of postholes from pillar-supported buildings, a silver Wadō Kaichin coin, quantities of ceramic inkstones and green-glazed ware. These were the tools and trappings of officialdom. From the early 1980s the Iida City Board of Education began a long programme of survey aimed at defining the site, and more than seventy rounds of excavation have followed.

One important caveat travels with the site. The storehouses, the kitchen and the boundary ditches have all been located, but the district hall itself, the guntei where officials conducted their business, has not yet been confirmed. The identification of Gonga as the Ina district office rests on the character of the surrounding remains and on written records rather than on the hall.

The Storehouse Compound

The clearest part of the site is its shōsō-in, the enclosed compound of tax storehouses. A shōsō was a raised-floor granary. The term is familiar from the Shōsō-in repository at Tōdai-ji in Nara, although that building holds temple treasures rather than the rice and grain that filled a district office's stores. At Zakōji, archaeologists have identified the foundations of more than twenty buildings as storehouses across the life of the site. At the compound's height, at least eleven stood together, with eight of them set in a straight line at regular intervals.

The compound changed shape over four phases. In the late seventh century the storehouses were small, roughly three bays square, and no enclosure yet marked them off. During the first half of the eighth century the office was rebuilt to a plan: larger granaries four bays by three, their floors carried on a full grid of posts, lined up inside a boundary ditch. That ditch ran about 215 metres on its long east-to-west side and 150 metres on the shorter side, and it bent into a trapezoid to skirt an existing burial mound, Takaoka Kofun No. 1, on its northern edge. In the later eighth and ninth centuries the granaries were rebuilt again, this time on foundation stones, and roof tiles found nearby suggest that at least some of them carried tiled roofs. By the late ninth century the orderly layout had broken down and the boundary ditch had silted in.

What the Objects Reveal

The find that most distinguishes Gonga is a humble one: the inkstone. Writing was the daily work of a district office, and most inkstones of the period were not carved stone but fired clay. By 2012 the site had yielded 88 ceramic inkstones, an unusually high number for a regional office anywhere in Japan. The concentration probably reflects an unusual workload. Ina lay just east of the Misaka Pass, the first district a traveller reached after crossing that difficult stretch of the Tōsandō highway from the capital, and for a period the head of Ina District also managed the horse pastures of the whole of Shinano. Both responsibilities generated paperwork.

Other objects fill in the picture. Pieces of pottery carry ink-brushed characters, among them kan for "office," kuriya for "kitchen" and possibly shin for Shinano. A silver Wadō Kaichin coin, struck in 708 and minted in silver for only about a year, came from a large pit building, and a Fuhonsen coin, regarded as Japan's earliest cast coinage, is also linked to the site. Both are rare finds in eastern Japan and are designated Nagano Prefectural Treasures. Charred rice recovered from postholes and ditches records repeated fires in the granaries, and radiocarbon measurements place the harvests in the late seventh century and again across the eighth and ninth.

About 250 metres southwest of the storehouses, a spring called Gonga Shimizu still rises at the foot of a terrace. Excavation along an old channel here recovered wooden ritual objects: small human figures, horse shapes and igushi wands. Ritual was part of administration in this period, a way of guarding against disaster and famine, and the spring appears to have been a place where such observances were carried out. Local residents still hold a festival at the spot today.

Why the Site Matters

Ancient district offices are not rare in the archaeological record, but well-preserved examples that can be studied as a whole are. When Gonga was designated in 2014 it became the forty-sixth kanga site protected as a National Historic Site, and the first in Nagano Prefecture. For Iida it was the first national historic site of any kind.

Its value lies in completeness and in setting. The four building phases let researchers watch a provincial office take shape, reach its peak in the eighth and ninth centuries and then contract. The written record reaches the site as well. A wooden tablet excavated at the Fujiwara Palace records the district under its older name, "Ina hyō," and a hemp cloth bag preserved at Tōdai-ji's Shōsō-in is inscribed with Ina District and a date corresponding to 746. Together, the ground and the documents give an unusually concrete view of how the early Japanese state governed a remote valley.

Visiting Zakōji

A visit to Gonga asks for some imagination. Most of the office remains lie buried and cannot be seen, and the city plans to develop the storehouse area as a historic park, with one granary to be reconstructed. The part already open is the area around Gonga Shimizu, the ritual spring, which has been laid out as a small park where the relationship between water, terrace and worship is easy to read on the ground.

The site sits in Zakōji, a district with a long memory. Moto-Zenkōji, the temple from which the great Zenkō-ji in Nagano traces its origin, stands nearby; by tradition its founding image was brought here in the early seventh century. A short way up the hill, on the grounds of Omi Shrine, stands the old Omi schoolhouse of 1873, the oldest wooden school building in the prefecture and unusual for combining a classroom with a kabuki stage. In front of it grows the Butai-zakura, a weeping cherry of perhaps three and a half centuries whose flowers open with anywhere from five to ten petals. The nearest station, Moto-Zenkōji on the JR Iida Line, is a short walk from the storehouse ground. By car, the site is about 25 minutes from the Iida or Matsukawa interchanges.