著者

桐野 文良 大野 直志 田口 智子 根津 暁充 横山 亮一

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

2019

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<p>The production processes of old Japanese coins, <i>Genbun-koban</i>, <i>Akita-ginban</i> and <i>Morioka-ginban</i>, were studied. These coins were manufactured by a forging method in the <i>Edo</i>-era. <i>Genbun-koban</i>, manufactured at a gold mint of the <i>Tokugawa</i> shogunate called <i>Kinza</i>, in 1736, is made of Au-Ag alloy and its surface is not flat. The residual stress of this coin is compressive, and the residual stress in the stamped area is higher than that in the flat area. The <i>Iroage</i> method was used to color the coin; it is a thermal treatment, resulting in lows the residual stress is smaller at flat area. <i>Akita-ginban</i>, manufactured in the <i>Akita</i> domain in 1863 is made of pure Ag and its surface is also not flat. There is no residual stress in this coin. This result shows that the thermal treatment of this coin was carried out after processing. <i>Morioka-ginban</i>, manufactured in the <i>Morioka</i> domain in 1868, is made of pure Ag, and its surface is flat. The residual stress of this coin is compressive, and the residual stress in the stamped area is higher than that in the flat area. This result shows that the thermal treatment was not carried out after processing. These coins manufactured in the <i>Edo-</i>era thus had different thermal treatments.</p>

著者

桐野 文良 大野 直志 田口 智子 根津 暁充 横山 亮一

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

pp.J2018048, (Released:2019-03-01)

参考文献数

12

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The production processes of old Japanese coins, Genbun-koban, Akita-ginban and Morioka-ginban, were studied. These coins were manufactured by a forging method in the Edo-era. Genbun-koban, manufactured at a gold mint of the Tokugawa shogunate called Kinza, in 1736, is made of Au-Ag alloy and its surface is not flat. The residual stress of this coin is compressive, and the residual stress in the stamped area is higher than that in the flat area. The Iroage method was used to color the coin; it is a thermal treatment, resulting in lows the residual stress is smaller at flat area. Akita-ginban, manufactured in the Akita domain in 1863 is made of pure Ag and its surface is also not flat. There is no residual stress in this coin. This result shows that the thermal treatment of this coin was carried out after processing. Morioka-ginban, manufactured in the Morioka domain in 1868, is made of pure Ag, and its surface is flat. The residual stress of this coin is compressive, and the residual stress in the stamped area is higher than that in the flat area. This result shows that the thermal treatment was not carried out after processing. These coins manufactured in the Edo-era thus had different thermal treatments.

著者

大野 直志

出版者

美術科教育学会

雑誌

美術教育学:美術科教育学会誌 (ISSN:0917771X)

巻号頁・発行日

vol.5, pp.125-138, 1983-12-15 (Released:2017-06-12)

著者

桐野 文良 大野 直志 田口 智子

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.83, no.3, pp.87-96, 2019-03-01 (Released:2019-02-25)

参考文献数

16

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The metal craft production techniques for an ancient Chinese coin named Ittou in the Shin period of ancient China were studied from material science viewpoints. This cultural artefact was manufactured in the Shin period of ancient China. An infrared image shows the surface state and the materials absorbed on the surface. According to infrared images of the cultural artefact, roughness on the surface of this coin was created on cooling during mintage. UV-fluorescence images show luminescence at corrosion products and yellow soil. In X-ray transmission images, some voids in this coin were observed, indicating the metal craft production technique used during this period. The main element of this cultural artefact is Cu and other elements are Sn and Pb. X-ray diffraction patterns indicate the presence of Cu-Sn base intermetallic compounds. Ittou coins are made from bronze. The characters on the coins were formed using an inlay technique called zougan. Yellow soil adhered to the surface of the examined coin from where it was excavated. The material used to form the characters on the coin is 10 mass% Cu-Au alloy, and flaws were observed on the surface of the characters. The compositions of ancient Kan coins produced between the east Kan and west Kan periods were also analyzed. The composition of these ancient coins was the same as that of the coin from the Shin period of old China, indicating that the same metal craft production technique was used in both periods. These techniques were improved in this period, enabling many coins to be manufactured.