This name is a synonym of Vigna minima var. minor (Matsum.) Tateishi.
The record derives from Tropicos
(data supplied on 2012-04-18)
which reports it as a synonym (record 100351470) with original publication details: J. Coll. Sci. Imp. Univ. Tokyo 12: 428 1899.
This name was in version 1 of The Plant List, record tro-100351470.