Kohiki is a ceramic technique in which a white slip (a muddy porcelain clay) is applied as a decorative coating (also called white slip or white slip coating) onto the clay body, which is then bisque-fired and subsequently covered with a transparent glaze before the final firing.
The name "Kohiki" was given by tea masters because the glaze surface looks soft, pure, and beautiful—resembling a dusting of fine white powder.
The clay body used for Kohiki contains iron-rich red clay (brownish soil).
The color tone can vary subtly from white to creamy or slightly yellowish depending on the clay body and firing conditions.
Kohiki is one of the ceramic techniques that traces its roots back to the ceramics of the Joseon Dynasty in Korea.
Around the 12th to 13th centuries, during the Goryeo Dynasty—the ruling dynasty of the Korean Peninsula at the time—refined and beautiful ceramics known as Goryeo celadon were perfected.
After the decline of Goryeo, the Joseon Dynasty inherited the celadon kilns and began producing ceramics called "Funshou haisei saki" (also known as "Funsei saki").
"Funsei saki" refers to ceramics coated with white slip and covered with a pale bluish-gray transparent glaze. Initially, these wares were designed to imitate the appearance of Goryeo celadon.
However, over time, the designs evolved into uniquely Joseon styles, and a wide variety of Joseon ceramics were created using various techniques.