I can’t publish it all here but I wrote a blog post here as part of the report on our progress of the Japanese swords project. Hope you are interested. We chose two Japanese swords related to Okinawa prefecture.
This time, our goal is to develop a new method to preserve the heart of Japanese sword technology. We use neutron tomography and the Bragg edge transmission method. When we use this method, we can see clear cracks and rust inside of swords and also differences in the crystal structure. The information helps us to identify the method of making swords and shools which made these swords. In addition to the literature, we can add insight into the swords without breaking them. This time we borrow two swords from Okinawa Prefectural Museum & Art Museum. These swords have histories with Okinawa prefecture.
The first one is the Japanese sword from the Ukada family. That sword is a heritage of the family. The report of the museum （Bull. Mus., Okinawa Pref. Mus. Art Mus.)，№ 14, pp. 117-132. 2021 titled 「南風原町新川の宇久田家御拝領墓に関する調査報告」(meaning the investigation on the tomb of a great family Ukada) said Mr Matsukawa a prefectural staff request Mr Hagio a museum staff to investigate the tomb on 25th of July in 2019 (令和元年:Reiwa-Gannen) The report describes the treasures from the tomb and there is a description of the Japanese sword. The Japanese sword had been stored in the Ukada family tomb. The Ukada family have protected family genealogy and the swords for generations
Before World War II, the Ukada family XIV Zensuke （全祐）had 6 sons and 3 girls. The second, third and fifth boys had died at an early age. The firstborn son Harumasa（全昌）moved to Osaka, the 4th born son Masatatu (全達) had lived in Tomigusu, the 6th born son Masahiro（全廣） and his father had lived Shuri-Samukawa-Cho (首里寒川町), Zensuke shared three family treasures to these three. Harumasa（全昌） got the family genealogy and the sword, Masatatu (全達) got the copper mirror, and Masahiro（全廣）got the flute.
However, there was brutal combat in Okinawa in late World War II. Mr Masatatsu lost the copper mirror during the combat. Also, Mr Masahiro was a school teacher in the north of Okinawa called Yamahara, he built a house in Nago. He made living there. He had the flute in his house however he could not find it after he came back from the mountain he hid during the fight. All the house had been burned out.
Fortunately, although the copper mirror and the flute were lost during the war, the family genealogy and the sword were at Osaka so they have survived. After World War II, the Ukada family XVI (Hiromichi) has preserved them. The Ukada family kindly donated them to the museum.
Another Japanese sword is the one preserved at the museum. It is believed that the sword had been owned by Genga-wueki. The Genga-wueki was a tycoon in Nago-city in Okinawa. Wueki means a tycoon who had huge lands and properties. Now, the Nago-city government manages their historical buildings. The museum believes that the sword preserved is the one the King of Ryukyus awarded to the Genga-wueki. However, there are not many records about the Genga-wueki, such as the history of their family origin. It is said that the managed properties have been there since the 19th century however no one has been living for at least decades.
These two Japanese swords have no name on the swords. At that time, there is no swordsmith in Okinawa so these Japanese swords have to be brought from the mainland of Japan. Currently, someone says it is from the Kyushu area however there is no evidence. This time we would like to investigate these Japanese swords by means of neutron scattering techniques, to know these words better.
We have submitted a proposal to perform a neutron scattering experiment at J-PARC in November 2021. Hope we will have a chance to measure these two Japanese swords.