History of Iwamiginzan (Iwami Silver Mine)
1.What is Iwami-ginzan?
Large-scale mining operations began at Iwamiginzan in the early 16th century. From the latter, it was half of the 16th century to beginning of the 17th century. It produced 32,000-40,000kg of silver a year. An innovative refining technique developed in Korea called “Haifuki-ho” was first used in Japan at Iwamiginzan and gradually spread to many other mines though out the country. Excavations which began in 1993 are now drawing attention to Iwamiginzan again.
This new research is helping us to answer questions about the early development of the mine. From its opening in the Edo period, Iwamiginzan was under the direct control of the “Bakufu” (Government). 59 public officers, called”Daikan” controlled Nima, Ochi and Anno districts which were the property of the Iwamiginzan. However, from the Kanei period, the production of silver began to decrease. In the Meiji and Taisho eras, the Fujita Company managed the mine.
It closed in 1922. The Iwamiginzan Museum stands on the site of the Daikansyo (public office), the former administrative center of the Nima district. The Daikansyo, Mabu (pit), and other 14 spots have been selected as national monuments. The houses along its street (built during the Edo period), have been designated as national heritage buildings. The Iwamiginzan is currently being considered for registration as a world historical site.
2.the iwami Region in the Middle Age
Ｔｈｅｒｅ are few records of the early development of the mine in the 16th century, and no documents concerning the actual management of the mine have been preserved. However, the political history of the Iwami region during that period is becoming clear. (We have discovered that the Iwamiginzan was taken under the jurisdiction of feudal lord.) Beginning in the Nanbokucho period, the Ohuchi family controlled the areas Suo and Nagato.
In 1366, the Ohuchi family was given control of the Iwami region. They were overthrown during the “Ohnin no Ran” revolt of 1399 by the Kyougoku and Yamana families, but regained control when Yoshioki was head of the family. At the time when the Yamana family was in control of the Iwami region, only the Nima area was allowed a certain amount of independent powers.
This situation continued until Yoshioki gained control in 1517. On coming to power Yoshioki was unable to bring stability to his region, at that same time the Amako and Mouri families, who had control of the Izumo ando Aki areas respectively, were winening the scope of their influence reaching the Iwami region. These families repeatedly attacked the region until the Mouri family gained control. In 1526, Kamiya Jyutei who was a trading merchant in Hakata,started the development of Iwamiginzan.
The mine began to increase silver production enormously due to the introduction of skill called “Haifuki Ho”. (Reference Data, “Yunotsu Town History”)
3.the introduction of “Haifuku Ho”
The book “Iwamikoku Ginzan Yousyu” was written by a government official of Iwamiginzan in 1812. (It is better known a “Ginzan Kyuki”) It says that Iwamiginzan started to develop thanks to Kamiya Jyutei, trading merchant in Hakata, in 1526. Just after 1526, it seems that they carried the ore to Hakata and refined it there. Then in 1533, Jyutei brought 2 Korean engineers to Iwamiginzan from Hakata. Their names were Soutan and Keijyu.
They introduced a new technique for refining silver, which is called “Haifuki Ho”, due to this method which was used in China and Korea.
Here is a summary of this process. At first lead is added to the silver ore, and hot air is blown into the mixture to melt then together.
Next they put the mixture of lead and silver on a bed of the hardened ashes of bones and pine tree leaves. When hot air is blown Into the mixture by Fuigo, it becomes oxidized. (Fuigo is a tool used to blow air into liquids.) As the oxides of lead have low specific gravity and low surface tension, they are absorbed by the ashes and the silver remains on the ashes.
Investigation of Excavation in Ishigane Area