The Yu Xuan signature is generally attributed to the famous Fujian soapstone carver Yang Yuxuan or Yang Ji who was believed to have been active during the early Kangxi period. One of the most revered carvers of his time, he is also credited with popularizing the trend of incorporating natural irregularities in stone into carving designs.
Compare with another luohan signed by Yang Yu Xuan with similar pronounced facial features and treatment of facial hair illustrated by G. Tsang and H. Moss, Arts from the Scholar's Studio, Hong Kong, 1986, p. 87, no. 45; and another luohan signed Yu Xuan supporting a miniature pagoda above his raised knee in the Palace Museum, Beijing (unpublished). Compare also the soapstone figure bearing the same signature, sold in Christie's London, 9 November 2010, lot 96.