- Other Names: potassium nitrate, niter, nitre, saltpetre
- Japanese: 硝石 (shouseki)
Saltpeter, also known as nitre or potassium nitrate, is a compound key to the production of gunpowder.
Though the Ming and Qing courts forbade the shipping overseas of saltpeter and certain other materials of military value, significant amounts of saltpeter regularly entered ports in Vietnam, Ryûkyû, and elsewhere.
- Craig Lockard, “‘The Sea Common to All’: Maritime Frontiers, Port Cities, and Chinese Traders in the Southeast Asian Age of Commerce, Ca. 1400–1750.” Journal of World History 21, no. 2 (2010): 236-237.; Uezato Takashi 上里隆史. "Ryûkyû no kaki ni tsuite" (琉球の火器, "The fireweapons in the Ryukyus"). Okinawa Bunka 沖縄文化. vol. 36:1, no. 91 (July 2000), 77.
- Ishin Shiryô Kôyô 維新史料綱要, vol 1 (1937), 345.