shitōga 指頭画

Painting where the tip of the finger or a long finger-nail is employed instead of a brush. Also called shiga 指画 (finger painting) or shiboku 指墨 (finger and ink). Said to have begun in China during the Tang dynasty with Zhang Zao (Jp: Chō Sō 張そう), but the most famous finger painter is probably Gao Qipei (Jp: Kō Kihai 高其はい, 1672-1734) of the Qing dynasty who also wrote a treatise on finger-tip painting, the Shitō gasetsu 指頭画説. 

In Japan, the literati painter Ike no Taiga 池大雅 (1723-76) was skilled in this art. This care-free painting style is sometimes categorized with the *hatsuboku 溌墨 or "flung-ink" tradition because of its associations with playfulness in painting, drinking and general revelry.