Ban Shan is the art name (hao) of Gan Xuan, an artist and calligrapher believed to have invented the art of inside snuff bottle painting. Gan Xuan also signed his snuff bottles with Yiru Jushi, Yun Feng and Gu Kaiqiao, initially misleading scholars into believing these were all names of different artists.
According to Chinese researchers, Gan Xuan was active from Jiaqing to Xianfeng Period, with his earliest known piece dating to 1816, and his last known piece dating to 1860. British scholarship has set his chronology even earlier, to 1802-1811.
According to the Hong Kong-based researcher Liang Xingzhi, Gan Xuan prepared his rock crystal snuff bottles by filling them with finely ground granite powder and water. He then kept shaking the bottles until the interior surface became rough enough for ink and pigments to adhere to it. He then used a bamboo pen with a bent tip to write and paint inside the bottle, using meticulously controlled strokes.