Imamachi Ichirizuka: Kyushu's Only Nationally Protected Edo-Era Milestone Mounds
Two low earthen mounds rise from either side of National Route 269 in southern Miyakonojo. The western mound measures 7.2 metres across its base and stands 2.7 metres high; the eastern one is a little smaller. Together they form a single ichirizuka, a paired road marker of the kind that once studded every long-distance highway in pre-modern Japan, and they are the only such pair on the island of Kyushu that holds national historic-site status.
The site was designated a National Historic Site on 24 December 1935. A second designation followed on 21 July 1973, redrawing the protected boundaries after postwar road widening had blurred them and adding a surviving fragment of the original roadside tree planting.
The Ichirizuka System
The ichirizuka was a creation of the early Tokugawa government. In 1604, the second shōgun Tokugawa Hidetada issued an order, supervised by the mining magistrate Ōkubo Nagayasu, to construct paired earthen mounds at intervals of one ri (about 3.93 kilometres) along the main highways radiating from the Nihonbashi bridge in Edo. The mounds were raised on both sides of the road, faced with grass, and crowned with a Chinese hackberry (enoki) or pine. The trees served three purposes at once: their deep roots stabilized the soil, their canopy gave summer travellers a place to rest, and the visible green crown made each marker easy to spot from a distance.
Within about a decade the network reached most of the main Tōkaidō, Tōsandō, and Hokurikudō routes. Daimyō across the country soon extended the rule to the secondary roads inside their own domains. By the eighteenth century, ichirizuka studded virtually every long-distance route in the country.
Most of those markers are now gone. The road widening required first by horse-drawn carts and later by motor traffic erased thousands; an 1876 Meiji government order specifically encouraging removal accelerated the loss. Only seventeen ichirizuka sites in Japan currently hold national historic-site protection, and the Imamachi pair is the only one on Kyushu.
The Road from Miyakonojo to Shibushi
The route on which the Imamachi mounds stand was not one of the five great Tokugawa highways. It was an internal route of the Satsuma domain, the southern feudal state ruled by the Shimazu clan. The road ran east-southeast from the castle town of Miyakonojo to the Pacific harbour at Shibushi, crossing what is now the Miyazaki–Kagoshima prefectural border. It carried provincial traffic such as domain officials, merchants moving timber and rice, and pilgrims, rather than the parade of regional lords seen on the Tōkaidō.
Miyakonojo itself was the largest private holding within Satsuma territory. The Kitago family, later renamed the Miyakonojo Shimazu, governed roughly forty thousand koku of land from here as a branch of the main clan. Setting an ichirizuka one ri out from town was a small but telling administrative gesture: even on a domain road, the Shimazu followed the Edo-era convention of marking the country in measured units.
The earliest official record describes the western mound as four ken (about 7.3 metres) across and nine shaku (about 2.7 metres) high, with the eastern mound a little smaller. Modern survey gives the western mound a basal diameter of 7.2 metres and a height of 2.7 metres, essentially unchanged from the Edo-era figures. The shape has held for around four centuries beside an active road.
What There Is to See
The mounds sit directly on the roadside, low and dignified rather than dramatic. A traveller in 1750 would have walked past them on foot, glanced up at the tree on top, and known exactly where they stood on the day's journey. Today's visitor approaches by car along the same alignment, with the mounds rising on either side as they did then.
Look for the difference in scale between the two. The asymmetry was noted as early as the original Edo-period survey and reflects the practical, non-ceremonial character of the work: these were tools of travel, built sturdily but not symmetrically. Note also how close the mounds are to the present road surface. The 1973 supplementary designation was issued precisely because road improvement work in the postwar decades had begun to encroach on protected ground. Some of the namiki-shiki, the strip of land reserved for the row of roadside trees, remains under protection on the south side.
The site has no admission building, no fence, and no entrance gate. A Japanese-language explanatory signboard stands nearby. Photography is unrestricted.
Visiting
The site lies along National Route 269 between the Imamachi and Umekita districts of Miyakonojo, roughly twenty minutes by car southeast of JR Miyakonojo Station. There is no dedicated visitor parking, so cautious roadside stopping is the usual approach. The mounds are accessible at any hour and free to view. Allow ten or fifteen minutes for the mounds themselves and combine the stop with another nearby destination.
Around Miyakonojo
Two stops in central Miyakonojo pair naturally with a visit to the ichirizuka. The Miyakonojo Shimazu Residence in the Hayasuzu district is a late-Meiji estate built by the 29th head of the family in 1879, registered as a Tangible Cultural Property, with an adjacent collection of around ten thousand items relating to roughly 670 years of the family's history. The Tonojō Castle ruins, on a hill in the Tonoshima district, hold the city's main history museum and panoramic views over the basin.
Sekinoo Falls, designated a National Place of Scenic Beauty and one of Japan's hundred most famous waterfalls, lies about twenty-five minutes by car west of the ichirizuka. The main cascade is 40 metres wide and drops 18 metres, and the river above it has carved a 600-metre stretch of potholes through welded tuff that is itself a Natural Monument.
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Q&A
- What exactly is an ichirizuka?
- A pair of earthen mounds set on opposite sides of a road, spaced one ri (about 3.93 kilometres) from the next pair, used in Edo-period Japan as distance markers and rest stops. A tree, usually a Chinese hackberry or a pine, was typically planted on each mound.
- Why is the Imamachi site important?
- It is the only ichirizuka on the island of Kyushu that holds national historic-site status. Of the seventeen such sites in all Japan, Imamachi is the southernmost, and the only example outside Honshu.
- Can the mounds be climbed or touched?
- No. The mounds are a protected national monument. View them from the roadside; do not walk on them.
- How long does a visit take?
- Ten to fifteen minutes. Most visitors combine it with the Miyakonojo Shimazu Residence, the Tonojō Castle ruins, or Sekinoo Falls.
- Is there a fee or fixed opening hours?
- No. The site is open-air, freely accessible at any hour, and has no admission charge.
Basic Information
| Name | Imamachi Ichirizuka (今町一里塚) |
|---|---|
| Location | Imamachi and Umekita districts, Miyakonojo City, Miyazaki Prefecture |
| Designation | National Historic Site |
| Designated | 24 December 1935 (Shōwa 10); additional designation 21 July 1973 (Shōwa 48) |
| Designation criterion | Criterion 6: sites relating to transport, communication, public works, production, or other economic activity |
| Dimensions | Western mound: 7.2 m basal diameter, 2.7 m high. Eastern mound: somewhat smaller. |
| Access | Along National Route 269 between Imamachi and Umekita; about 20 minutes by car from JR Miyakonojo Station or Miyakonojo IC |
| Admission | Free; open at all hours |
| Inquiries | Miyakonojo City Cultural Properties Division, tel. +81-986-23-9547 |
References
- National Designated Cultural Properties Database, "Imamachi Ichirizuka" (Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/bsys/maindetails/401/2925
- Imamachi Ichirizuka (Miyakonojo City Official Website)
- https://www.city.miyakonojo.miyazaki.jp/site/bunkazai/2691.html
- Imamachi Ichirizuka (Cultural Heritage Online)
- https://bunka.nii.ac.jp/heritages/detail/162658
- Kagoshima Domain and Miyakonojo (Miyakonojo City Official Website)
- https://www.city.miyakonojo.miyazaki.jp/site/shimazu/9105.html
Last verified: 2026.05.20