Taga Castle Monument (December 1st, Tenpyo Hoji 6th Year)

Taga Castle Monument: A Stele of 762 at the Tagajo Site

The Taga Castle Monument (多賀城碑, Tagajo-hi), dated the first day of the twelfth month of Tenpyo Hoji 6, is a stone stele erected in 762 at the site of Taga Castle in Tagajo City, Miyagi Prefecture, and was designated a National Treasure in 2024.

Taga Castle was a fortified government centre that housed the provincial office of Mutsu from the eighth century, and in the Nara period it also held the Chinjufu, the military headquarters for the northern frontier. The stele stands on a low rise near the south gate of the outer enclosure, now protected inside a small hall.

The Taga Castle Monument was designated an Important Cultural Property on 30 June 1998 and raised to National Treasure on 27 August 2024. It is owned by the national government (Agency for Cultural Affairs). Tagajo City describes it as one of Japan's three great ancient steles, alongside the Tago Stele in Gunma and the Nasu Kuni no Miyatsuko Stele in Tochigi.

The Inscription and Why It Is a National Treasure

The stone is a granitic sandstone, 248 centimetres high (196 centimetres above ground), with a maximum width of 103 centimetres and a maximum thickness of 72 centimetres. The top is rounded into a semicircle and the inscribed face points almost due west. A large character meaning west is cut at the top, and below it, inside a rectangular frame, are 140 characters in 11 lines.

The text gives the distances to Taga Castle from the capital and from the lands of the Emishi, Hitachi, Shimotsuke and Mohe; records that Ono no Azumahito founded the castle in 724; records its rebuilding in 762 by Fujiwara no Emi no Asakari; and ends with the date of erection.

The stele became known in the early Edo period and was quickly identified with the Tsubo no Ishibumi, a stone famed in classical poetry. The poet Matsuo Basho visited it in 1689 on the journey recorded in The Narrow Road to the Deep North. In the Meiji period, however, scholars argued that it was an Edo-period forgery, and the debate petered out in the Taisho period without a verdict.

The turning point came with continuous excavation of the castle site from 1969. The date, scale and layout it revealed matched the inscription, and a fresh study showed, among other things, that all the characters were carved at the same time and that the script matches documents and wooden tablets of the period. The Taga Castle Monument is now accepted as genuine. The Agency for Cultural Affairs values it as one of the few inscriptions in stone surviving from the Nara period and as key evidence for Taga Castle and the ancient northeast.

What to Look For

Start with the large character for west at the top. Taken together with the fact that the face looks almost due west, it is the first clue to reading the stele. The 140 characters below fall into two parts: the list of distances and the record of the castle's founding and rebuilding.

When the protective hall was dismantled for repair, excavation around the stone found the pit dug when it was reset in the early Edo period, together with traces of a technique used for setting the foundation stones of ancient buildings. The agency says this strengthens the case that the stele has stood in this spot since it was first erected.

Basho stood before this same stone in 1689. The forgery debate and the modern reassessment all turned on it. Tagajo City publishes a transcription of the full text online, and reading it on site makes the visit far more rewarding.

Visiting the Taga Castle Monument

The stele stands in the Taga Castle site in Ichikawa, Tagajo, near the south gate of the outer enclosure. The nearest station is Kokufu-Tagajo on the JR Tohoku Main Line. Because the stone is housed in a small hall, it is viewed from outside the building.

Tagajo City's page gives no hours or fees. The castle site is an open-air Special Historic Site that can be explored on foot together with the area around the south gate.

No official policy on photography could be found. Do not touch or lean into the hall that shelters the stele, and follow any signs on site. Enquiries go to the cultural properties section of Tagajo City.