Photo/IllutrationThe southern slope of the Hirano-tsukaanayama “kofun” burial mound where tuff stones were unearthed in Kashiba, Nara Prefecture. The photo was taken on June 25. (Mari Endo)

  • Photo/Illustraion
  • Photo/Illustraion

KASHIBA, Nara Prefecture--Recent findings have strengthened speculation that Chinu no Okimi, the father of Empress Saimei, is the individual enshrined at a “kofun” burial mound that was created here in the late seventh century.

Tuff stones, each measuring about 15 to 30 centimeters on their sides, were unearthed on part of a slope of the Hirano-tsukaanayama kofun, a government-designated historical heritage site located in the northern part of Kashiba close to the border with Osaka Prefecture.

Researchers believe the tuff stones likely covered at least the upper part of the two-layered mound, raising the possibility that the tomb was built for an imperial family member.

The tuff stone feature has been found at only two other kofun: the Kengoshizuka tumulus, also a government-designated historical heritage site, and the Noguchi no O no Haka burial site, both located in Asuka in the prefecture.

The Kengoshizuka tumulus is believed to be the burial site of Empress Saimei (594-661), who sat on the throne in the mid-seventh century. Emperor Tenmu, who developed the country under “ritsuryo” laws and died in 686, and his wife, Empress Jito (645-702), are thought to be jointly enshrined at Noguchi no O no Haka.

Empress Saimei was a daughter of Chinu no Okimi, whose years of birth and death are unknown.

The remains of the Hirano-tsukaanayama kofun indicate that it was a two-layered square structure measuring about 25 by 30 meters and 5.4 meters in height.

Fragments of a “kyochokan” lacquered coffin, which was used only for high-ranking people, were discovered from its chamber, according to the Kashiba municipal board of education.

The presumed octagon-shaped Kengoshizuka and Noguchi no O no Haka tombs most likely contained kyochokan, board officials said.

Another thing fueling speculation that Chinu no Okimi is entombed at the Hirano-tsukaanayama kofun is a passage from “Engishiki,” a collection of governmental rules and formalities compiled in the 10th century, according to Yoshinobu Tsukaguchi, honorary president at Sakai Woman’s Junior College whose expertise is ancient history.

“Chinu no Okimi’s burial site is in the Kataoka Ashida district,” the passage says.

The Kataoka Ashida district is around the kofun area.

“The probability has increased that the kofun is the burial site of Chinu no Okimi,” Tsukaguchi said. “He was a grandson of Emperor Bidatsu (538-585) who sat on the throne in the late sixth century.”

Taichiro Shiraishi, honorary director at the Osaka Prefectural Chikatsuasuka Museum, who is knowledgeable about ancient history, has the same view.

“It is thought that the tomb of Prince Oshisaka no Hikohito no Oe, father of Chinu no Okimi, is the Makino kofun in Koryo, Nara Prefecture, near the Hirano-tsukaanayama kofun,” Shraishi said. “It is likely that the family would control the surrounding area as their home base.”

The discovery of the tuff stones at the Hirano-tsukaanayama kofun could affect the dispute over who is enshrined at the famed Kitora Tomb and Takamatsuzuka burial mound, both of which were built between the late seventh century and early eighth century, bear murals and are located in Asuka in the same prefecture.

Several theories have been floated over who is enshrined at the two kofun, but no conclusion has been agreed upon.

They could be figures at the crown prince level, foreign dignitaries or local ruling families at the minister level.

Researchers have found “tekoana” leverage holes in the chambers of the Kitora Tomb and the Takamatsuzuka burial mound.

The same types of holes were also confirmed in the rock chamber of the Hirano-tsukaanayama kofun. A portion of the stone wall was curved to create tekoana. Workers there put metal poles in the holes to create leverage for moving heavy stones, experts said.

Hisashi Okuda, a special researcher at the Archaeological Institute of Kashihara, Nara Prefecture, said of the holes, “This shows that workers moved stones in increments of 1 cm using leverage sticks.

“Other workers in the same family tree probably built the Kitora Tomb and the Takamatsuzuka burial mound with Hirano-tsukaanayama kofun as their base.”

Machiko Satonaka, a manga artist whose works are often set against the background of an ancient era, said: “Tekoana were found at the Hirano-tsukaanayama kofun, whose enshrined person is now more likely to be an imperial family member. The Kitora Tomb and the Takamatsuzuka burial mound, both of which bear features identical to the Hirano-tsukaanayama kofun, are now more likely to be the sites where imperial family members are enshrined.”

Ko Izumori, who once served as deputy director of the Archaeological Institute of Kashihara, Nara Prefecture, was in charge of the archaeological excavation of the Hirano-tsukaanayama kofun in 1972.

“The burial mound was built through the ‘hanchiku’ construction method, in which layers of soils are stratified, for tombs of imperial family members or similar level people,” he said. “It probably looked very gorgeous.”

On June 30, about 360 cultural asset fans and about 20 volunteer guides gathered to take a look at the Hirano-tsukaanayama kofun and listen to experts’ explanations, despite the rainy weather.

Yasuko Okubo, 80, who lives in Higashi-Osaka, Osaka Prefecture, said: “The quarried stones at the chamber were thick and gorgeous. My visit here was rewarded.”

Another visitor simply said, “The chamber was beautiful.”

(This article was written by Chihiro Kotaki, senior staff writer, Akira Nemoto and Yuya Tanaka.)