Handaka Sonja was one of the sixteen special disciples of the Buddha, called rakan. He is always depicted with his dragon which he keeps in a bowl or gourd bottle. Handaka's pose is skilfully conveyed in this piece. He crouches on one knee, and seems to scratch his dragon's chin almost affectionately.
Netsuke of this type appear in the Sōken Kishō, the earliest authoritative guide to the subject (and also to inrō, purses and sword furniture), published in woodblock-printed book form in Osaka, 1781.