Suganuma Village - Saltpeter Museum

This entry contains some of my inner geek, so you've been warned.

Information on the Saltpeter Museum: In the Edo period, the major industry of Gokayama under the reign of Kaga Clan was the secret production of saltpeter (potassium nitrate), the ingredient for gunpowder. At that time, due to the nation's closed policy, no gunpowder was imported. The Kaga Clan replaced the Chinese character which means "smoke" to "salt" to conceal the gunpowder from the Tokugawa Shogunate. The industry lasted for more than 300 years in Gokayama, beyond the reach of the Tokugawa Shogunate.

They used plants as starting materials, which were mixed with soil to be decayed. One of the information sheets stated that the excrement from the silkworms was also one of the raw materials used for making gunpowder.

The mixture was stored under the floor while occasionally being stirred. During the storage period, the gunpowder ingredient was produced by bacteria.

The mixture was put into a large bucket with hot water to create a clear saltpeter solution, which was boiled in a pot and cooled in a small bucket to gain salt-like crystals (saltpeter). The saltpeter (KNO3) was mixed with sulfur (S) and carbon (C) to produce black gunpowder.

Harquebus (musket).