Doenjang

Doenjang or soybean paste is a type of fermented bean paste made entirely of soybean and brine used in Korean cuisine. It is also a byproduct of soup and soy sauce production. It is sometimes used as a relish. The earliest soybean fermentations in Korea seem to have begun prior to the era of the Three Kingdoms. The Records of the Three Kingdoms, a Chinese historical text written and published in the third century AD, mentions that "Goguryeo people are good at brewing fermented soybeans" in the section named Dongyi (Eastern foreigners) in the Book of Wei. Jangdoks used for doenjang production are found in the mural paintings of Anak Tomb No. 3 from the 4th century Goguryeo.

Source: Wikipedia