Haha Sen
The Japanese name for the first impressions made from the Hori Tane Sen (q.v.) or original hand cut Sen, and from which the Tane Sen (q.v.) are made. These are naturally very rare and much prized as most of them are cast in pewter. See Mu Ch'ien, the Chinese equivalent.
Synonyms: Mother Sen
Source: Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)