A similar netsuke by Masatoshi of Tokyo depicting sumo wresters in a very similar pose is in the Museum of Fine Arts, Boston (11.23729). Joe Earle notes that the pose refers to a classic bout between Kawazu and Matano that took place in 1176. Matano was about to lift Kawazu by his loincloth and throw him, but Kawazu outwitted him with a combined neck grip and leg trip, a move still known as kawazugake.1
1. Joe Earle, Netsuke: Fantasy and Reality in Japanese Miniature Sculpture, (Boston, 2001), p.200, fig.163