This name is a synonym of Ajuga yesoensis var. tsukubana Nakai.
The record derives from WCSP
(data supplied on 2012-03-23)
which reports it as a synonym (record 5413) with original publication details: Nippon Shokubutsumeii 583 1974.
This name was in version 1 of The Plant List, record kew-5413, and has not been changed.