Tomizuka Kofun: A 1,600-Year-Old Royal Tomb at the Heart of Sendai
Just a short trip southeast of JR Sendai Station, a great green mound rises unexpectedly from a quiet residential neighborhood. This is Tomizuka Kofun, a keyhole-shaped burial mound built for a powerful chieftain at the end of the 4th century. With a total length of approximately 110 meters, it is the second-largest ancient tumulus in Miyagi Prefecture and one of the five largest in the entire Tohoku region. Walking around its grassy slopes, visitors find themselves in the presence of a monument raised more than 1,600 years ago, long before the city of Sendai itself was founded.
Today the site is preserved as a public history park, freely open to all. The contrast is striking: the rounded earthen mound, the encircling moat, and the wide open lawns sit side-by-side with bypass traffic and quiet city streets. For travelers interested in the deep prehistory of Japan, Tomizuka Kofun offers something rarely seen in Tohoku — a chance to stand on top of a fourth-century royal tomb, look out over the Sendai Plain, and imagine the rise of the first kings of northeastern Japan.
The Historical Background
The Kofun Period (roughly the 3rd to 7th century) is the great age of monumental tomb-building in Japan, when emerging regional leaders proclaimed their authority by raising enormous earthen mounds, often in the distinctive "keyhole" shape that combines a round rear chamber with a trapezoidal front platform. Tomizuka Kofun belongs to the early part of this period, dated to the late 4th to early 5th century based on its shape, internal structures, and the style of Haji-ware pottery recovered from the site.
The mound sits on a natural levee about 10 meters above sea level along the north bank of the Hirose River, in the center of the fertile Sendai Plain. The surrounding area was inhabited from the Yayoi Period onward and forms part of the larger Minamikoizumi archaeological site, where rice-farming villages flourished for centuries. Tomizuka Kofun marks the moment when this region produced a leader powerful enough to mobilize the labor needed to raise a tumulus on a scale otherwise reserved for the chieftains of the Yamato heartland far to the south.
Roughly 10 kilometers to the south stands Raijinyama Kofun in Natori City — the largest tumulus in all of Tohoku at 168 meters. The two mounds together mark the northern frontier of the great keyhole tombs of ancient Japan. Scholars continue to debate whether Tomizuka was built before, during, or after Raijinyama, but in either case the pair tells us that the Sendai Plain was an important political center of the early Kofun era.
The tomb has not had a peaceful history. In the postwar years it was farmed over in places, and in 1947 occupying forces removed earth from the mound to extend a nearby airfield, destroying the northern half of the rear circular section. The route of the National Route 4 Sendai Bypass later threatened to slice through the site as well. It was the designation as a National Historic Site in 1968, followed by an extension of the protected area in 1980, that finally secured the monument for future generations.
Why Tomizuka Kofun Was Designated a National Historic Site
Tomizuka Kofun was designated a National Historic Site (Kuni-shitei Shiseki) by Japan's national government on November 8, 1968, with an extended designation covering surrounding land added on March 14, 1980. The reasons for this protection are both scale and significance.
At approximately 110 meters in length, the tomb is the largest keyhole-shaped tumulus within Sendai City, the second-largest in Miyagi Prefecture, and ranks among the top five in the Tohoku region — a part of Japan where great kofun are otherwise rare. Its mere existence is evidence of a strong regional ruler, organized labor on a substantial scale, and political ties with the early Yamato polity to the south.
The 1968 designation was triggered in part by the threat of further destruction: the bypass plan and earlier wartime damage made it urgent to recognize and protect the mound. Investigations from 1975 to 1982 then revealed the burial chambers, grave goods, and the surrounding moat. These finds confirmed both the construction date and the high status of the person buried here, securing Tomizuka Kofun's place as one of the most important early Kofun-period sites in northeastern Japan.
Highlights and What to Look For
Tomizuka Kofun is shaped like an old-fashioned keyhole, with a round rear chamber roughly 63 meters across and 6.5 meters high, and a lower trapezoidal front section about 37 meters wide and 2.5 meters high, pointing south. One particular feature catches the eye: the front section is unusually low in proportion to the round mound, a characteristic of relatively early keyhole tombs. The whole structure is surrounded by an irregular moat, varying from about 10 to more than 40 meters in width.
Visitors are welcome to walk up onto the mound itself. The view from the top of the rear circular section gives an excellent sense of scale and a wide outlook over the streets of Wakabayashi Ward — a view chosen by the city as one of its official "Mori-no-Miyako" scenic viewpoints. Try to picture this in the late 4th century, with rice paddies stretching to the horizon and the Hirose River winding nearby.
The rear chamber once contained two side-by-side wooden coffins of the split-bamboo type, sheathed in clay and laid in pits aligned north-south. Although the rich array of weapons and mirrors typical of central Japanese tombs was not found here, archaeologists did recover a tubular jasper bead, four small glass beads, and 18 bamboo combs lacquered in black — modest but evocative offerings to a regional ruler. Pottery scatters in the moat suggest that ceremonies were held at the tomb after burial.
Many of the unearthed artifacts are kept at Sendai City Museum and the neighboring Tomizuka Elementary School, where local children grow up literally next door to a site of national importance. Information panels around the park explain the structure and history of the mound, with diagrams of the burial chambers and the original layout.
Visiting Tomizuka Kofun
The site is an open-air history park. There are no gates, no entry fee, and no fixed opening hours — visitors can come during daylight at any time of year. The mound is wheelchair-accessible around the perimeter paths, though the top of the rear circular section is reached by a gentle grassy slope.
Spring brings cherry blossoms to the park, making April an especially photogenic time to visit. Summer offers lush green slopes and the chance to enjoy the lawns under the open sky. In autumn the surrounding trees turn golden, and on clear winter days the air is crisp and the silhouette of the mound stands out vividly against the sky.
Please note that there is no dedicated parking lot at the site. Visitors arriving by car are encouraged to use one of the small coin-operated parking lots in the surrounding streets. The most convenient route is by public transport.
What to See Nearby
A short walk or bus ride from Tomizuka Kofun brings travelers to several other points of interest. The ruins of Mutsu Kokubunji, an 8th-century provincial temple founded by Emperor Shomu, lie just to the north and offer another window into ancient Tohoku. The remains of the temple's pagoda and main hall foundations are open to the public.
For those keen to follow the kofun trail further, Raijinyama Kofun in Natori City — about 10 kilometers south — is a worthwhile pairing. As the largest tumulus in Tohoku, it complements the Tomizuka visit and helps put the political geography of the early Kofun Period into perspective.
Back in central Sendai, Sendai City Museum, located in the park grounds beneath Sendai Castle, displays artifacts excavated from Tomizuka Kofun and many other sites in the region. Sendai Castle itself, with its famous statue of Date Masamune and panoramic views of the city, is another natural stop. The bustling streets of central Sendai — known for its grilled beef tongue (gyutan), fresh seafood, and tree-lined Jozenji-dori avenue — are all within easy reach.
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Q&A
- When was Tomizuka Kofun built, and who was buried inside?
- It was constructed during the late 4th to early 5th century, in what is known as the early Kofun Period. The size and contents of the tomb suggest the occupant was a chieftain who ruled over a wide area of the Sendai Plain, though their name and exact identity are not recorded in any surviving text.
- Can I walk on top of the mound?
- Yes. Tomizuka Kofun is preserved as a public historical park, and visitors are free to walk along its paths and up onto the rear circular section. The view from the top is one of Sendai's officially recognized scenic spots.
- Is there an entry fee or fixed opening hours?
- No. The site is a public park, free of charge and accessible at any time during daylight hours. There are no ticket gates or visitor center on-site, but information panels around the mound provide basic explanations.
- How do I get there from central Sendai?
- The most convenient route is to take the Sendai Subway Tozai Line to Yakushido Station, then transfer to a city bus and get off at the "Tomizuka" stop. The mound is about a seven-minute walk from the bus stop. The site is also about 3.6 kilometers southeast of JR Sendai Station, reachable in 10 to 15 minutes by taxi.
- Where can I see the artifacts found at the tomb?
- Excavated items including a jasper cylindrical bead, glass beads, and lacquered bamboo combs are kept and exhibited at Sendai City Museum, located in the grounds of Sendai Castle. Some items are also held by the adjacent Tomizuka Elementary School.
Basic Information
| Name | Tomizuka Kofun (Tomizuka Tumulus) |
|---|---|
| Location | Tomizuka, Wakabayashi Ward, Sendai City, Miyagi Prefecture |
| Type | Keyhole-shaped tumulus (zenpo-koen-fun) |
| Period | Late 4th to early 5th century (Early Kofun Period) |
| Dimensions | Total length approx. 110 m; rear mound diameter 63 m, height 6.5 m; front section width 37 m, height 2.5 m |
| Designation | National Historic Site (designated November 8, 1968; extended March 14, 1980) |
| Burial chamber | Two split-bamboo wooden coffins encased in clay, laid in the rear circular mound |
| Main grave goods | Tubular jasper bead, 4 glass beads, 18 lacquered bamboo combs |
| Access | About 7 min on foot from Tomizuka bus stop (bus from Yakushido Station on the Sendai Subway Tozai Line); approx. 3.6 km southeast of JR Sendai Station |
| Admission | Free / Open year-round during daylight hours |
| Parking | No on-site parking; coin-operated lots in the surrounding streets |
References
- Tomizuka Kofun - Cultural Heritage Online (Agency for Cultural Affairs)
- https://bunka.nii.ac.jp/heritages/detail/204703
- Designated Cultural Properties (Historic Site): Tomizuka Kofun - Miyagi Prefectural Official Website
- https://www.pref.miyagi.jp/soshiki/bunkazai/kuni-siseki09.html
- Tomizuka Kofun - Designated and Registered Cultural Properties of Sendai City
- https://www.sendai-c.ed.jp/~bunkazai/shiteidb/c00565.html
- Tomizuka Kofun - Archaeological Sites in Sendai City
- https://www.sendai-c.ed.jp/~bunkazai/isekidb/c00105.html
- "Kofun ga Monogataru" (Sendai City Wakabayashi Ward Official Site)
- https://www.city.sendai.jp/waka-katsudo/wakabayashiku/machizukuri/miryoku/kofun.html
- Tomizuka Kofun - Wikipedia (Japanese)
- https://ja.wikipedia.org/wiki/遠見塚古墳
Last verified: 2026.05.14