Sulüzi 素履子 "The master with the straw sandals" is a philosophical treatise by the Tang-period 唐 (618-907) scholar Zhang Hu 張弧. Of Zhang's life, nothing is known. In his book, he explains 14 terms known from Confucian philosophy, like virtue, loyalty or filial piety. The original book was only 1-juan long, but the received version is divided into 3 juan. It had never attracted a wide readership and is not mentioned in contemporary bibliographies. The philosophical and literary level is not very high, and therefore is was only preserved in very few specimen after the Song period 宋 (960-1279). It has been included into the series Siku quanshu 四庫全書 because it quotes from the Confucian Classics. There is a print from the Ming period 明 (1368-1644) which was stored in the library of Ma Yujia 馬裕家 in the 18th century.