문방사우(文房四宝) means Four Precious Things of The Study (or Four Treasures of the Study or Four Jewels of the Study or Four Friends of the Study) is an expression used to denote the brush, ink, paper and ink stone. ☺

文房四友 = 紙, 筆, 墨, 硯 four friends of a Confucian scholar in his study room = paper, writing brush, ink stick, ink stone