In 1949, former Kyoto University professor Sakae Ikeda wrote a letter in a Japanese newspaper requesting help. “Whoever may want to help reintroduce Nestorianism . . . to Japan . . . is requested to write me,” the letter pleads.

An engraving on a beam of the original building of Horyu-ji temple in Nara Prefecture shows a Nestorian cross.

The idea of “reintroducing” Nestorian Christianity here might seem surprising taking into account the official history textbook line that Christianity was introduced here by Francis Xavier in 1549.

Yet, Ikeda is one of a number of scholars who claim the Nestorian Church, or Church of the East, arrived in Japan over 1,000 years before St. Francis was even born.

“Through the Church of the East,” Ikeda continues in his letter, “the missionary enterprise of the Christian faith flourished in Japan . . . (and) exerted not a little influence on the culture.”

A contemporary proponent of this theory is Japan-born American Ken Joseph, whose ancestors were among the missionaries who brought Christianity to the Far East around 1,500 years ago.

Over 50 years of research on the subject by Joseph and his father culminated in the publishing of a book this year, “Jujika no kuni — Nihon” (Japan: The Nation of the Cross), in which the authors tell the largely hidden story of early Christianity in Japan and introduce Christian sites throughout the nation.

Yet, Joseph says it was the uncovering of the Da Qin monastery in Xian, China that has provided the most conclusive evidence that the church made it here. The two Chinese characters for Da Qin, he says, correspond to “Uzumasa” in Japanese. Uzumasa-dera is one of the names given to a Kyoto temple long thought to have once been a place of Christian worship. Even today there are remnants there indicating its Christian past, Joseph says.

Built at the beginning of the 7th century, the temple, better known today as Koryu-ji, was founded by Hata no Kawakatsu, a member of the influential Hata family, whose more important members are thought to have arrived in Japan from Korea in AD 400.

However, in a book penned in the 1960s, Kyoto professor Ikeda claims that the Hata clan were from Turkestan. “The Hatas were a Nestorian tribe who . . . migrated to Japan via China and Korea in search of religious freedom,” Ikeda writes. “Although they were persecuted by Buddhists in both China and Korea, they were granted full freedom in all but name from the time of their arrival.”

The temple also housed a shrine to St. David and a holy well upon which stood a sacred tripod symbolizing the holy Trinity, Ikeda says. A tripod, built in the style of a triangular “torii,” can still be seen at the temple today.

Koryu-ji was one of the sites Joseph visited for his book. Others included Horyu-ji temple in Nara Prefecture, originally built in 607 by order of Prince Shotoku, a good friend of Hata no Kawakatsu. Although the temple was destroyed by fire in 670, a part of a beam survives and is today stored in the Tokyo National Museum. On the beam is inscribed what are thought to be two Nestorian crosses.

Joseph also visited a graveyard in Kyushu housing an 8th-century tombstone on which a similar cross was engraved, and “Christ’s Grave” in Gunma Prefecture, which legend says is the place where Christ was laid to rest.

Upon meeting with the owner of the land on which the burial site is erected, Joseph asked if perhaps there were a more “credible” explanation for its origin. “He eventually conceded that the site was the burial place of early Christian missionaries,” Joseph says.

Written evidence of an early Christian presence has been noted by other scholars. Yoshiro Saeki, known as the father of research on the Eastern Church, wrote two books on Nestorianism in the early 1900s.

While both concentrate largely on interpreting relics and documents found in China, Saeki, who studied both the Persian and Syriac languages at Oxford University to help his studies in Eastern Christianity, also notes Imperial records in Japan that mark the visit of a Persian missionary to Nara in AD 736.

Saeki believes this man, who was granted an audience with the Emperor and is said to have received “Imperial favors,” to be the father of Yesbuzid, who erected the Nestorian Monument in China (see main story).

What’s more, in his book “Nestorian Missionary Enterprise,” British scholar John Stewart says that it was through the teachings of this Persian visitor that Empress Komyo (701-760) was “led to embrace Christianity.”

The legacy of the early Christians lives on in the Japanese customs and language of today. Saeki believed that the origin of the word “Uzumasa” was taken from the Aramaic “Yeshu Mesiach,” meaning “Jesus messiah.”

Indeed, Hebrew words and phrases are not uncommon in Japanese folk songs and stories, according to Ikuro Teshima, a disciple of Saeki’s. In a paper on the subject, Teshima states that in a song in the famous children’s story “Momotaro,” the line “En Yalah Yah” appears. The meaning in Hebrew is “I praise God,” Teshima says.

What’s more, the August festival of Obon was influenced by the Nestorian Christian’s All Souls festival, and Buddhist ceremonies held at the monastic site of Mount Koya still incorporate the making of the sign of the cross, Joseph said. “I spoke to a priest there who said that while most of the Christian forms in Shingon Buddhism have gone, some still remain.”

Another unusual feature on Koya-san is a replica of the Nestorian Monument, which was erected in the 1940s by Nestorian scholar E.A. Gordon. Joseph says he was told by a priest there that Koya-san in fact was originally a Christian monastery.

“The traditional view is that the only thing to arrive in Japan via the Silk Road was Buddhism,” Joseph stated. “No one ever challenges that. It’s simple logic that all kinds of people must have come into Japan — including the early Christians. Whereas the Chinese embrace their cosmopolitan past, the Japanese tend to ignore it.”

Like Ikeda’s letter 50 years before them, the Josephs have received a number of contacts since the publication of their book. One woman, who was born and raised in a Kyoto temple, told of an episode in her childhood when her grandfather revealed the “hidden treasures” of the temple. Among them were artifacts engraved with crosses.

The woman, who spoke on condition of anonymity, said: “It’s all hush-hush, but many temples in Japan house such Christian treasures.”