The "four friends" means paper, brush, ink stick, and ink stone in Korean calligraphy. Those are called Munbangsawoo (文房四友) in Korean. In Korean calligraphy, traditional hanji (韓紙) made of Korean mulberry is used. It is well-suited for absorbing ink and reflecting its colors. For brush, animal hairs of same length are selected and made into straight and a sharply pointed tip. Ink stick is made by soot from burned trees and glue. A good ink stick has extremely fine particles. Finally, ink stone must be made from a firm stone which does not when ground by the ink stick, or jade. In addition to the four tools, calligraphy needs other items: a yeonjeok, a container of water, used for making ink with ink stick, boot tong, a container for holding brushes after being used, munjin, a long and flat paper weigh, and pilse, a bowl for washing the brush.[8]