- 薬史学雑誌 (ISSN:02852314)
- vol.54, no.2, pp.77-82, 2019 (Released:2020-07-11)
Gunpowder happened to be produced while seeking the elixir of life. Saltpeter (i.e., potassium nitrate) is an essential substance required to produce gunpowder. There are no saltpeter lodes in Japan. So an aged-soil method called Kodo-hou, which was developed to make saltpeter using the soil from underfloors of houses, was used after guns were introduced. It is not clear where and how this method was invented. The only culture-related method, called Baiyou-hou, was adopted in the Gokayama region of Kaga-han, now Ishikawa. The Edo period was so peaceful that the demand for making saltpeter subsided, and the production technology fell into decline. The Chichibu area, now Saitama, thrived in the production of
gunpowder when under the control of Oshi-han. Especially, at the end of the Edo period, much gunpowder was required to defend Edo Bay following the arrival of Admiral Perry. Oshi-han was ordered to defend Edo Bay and bought the gunpowder used from the Chichibu territory. By that time, the materials used for the Kodo-hou method became more available, leading to a familiarized way to make saltpeter. The author succeeded in producing saltpeter applying the Kodo-hou method and using the same material as in the Edo period, confirming the correctness of that material. It was personally experienced how hard it was to make saltpeter in those days. In Chichibu, nearly 400 festivals are held each year, and people set off fireworks as a sign of dedication to not only big shrines, but also small shrines. This suggests that there used to be abundant gunpowder in this area.