子 Soebireum Ssi (쇠비름 씨)

Purslane seed appears in the Vegetables section (chaebu, 菜部) of the Dongui Bogam, as a sub-entry attached to the main article on purslane (machihyeon, 馬齒莧). Purslane earned the nickname "five-phases herb" (ohaengcho, 五行草) because a single plant shows all five colors of the Five Phases — the East Asian framework that maps the elements wood, fire, earth, metal, and water onto colors, directions, and seasons: green leaves, red stems, yellow flowers, white roots, and black seeds. Among these five, the seed holds the black position, the color that corresponds to water.

The original text does not record a nature and flavor for the seed. In traditional Korean medicine, most medicinal entries open by stating a substance's "nature" (how warming or cooling it is) and its "flavor," which together signal how it is expected to act in the body — but this sub-entry leaves them unstated.

Purslane itself remains a familiar sight today, growing along field edges and roadsides and in the cracks between paving stones.