This is a female. The white patch at the base of the tertials helps distinguish this species which is primarily a winter visitor to Japan from southern Siberia and Mongolia, although a small breeding population has recently been found in central Japan (Nagano Prefecture). Formerly classified with the Thrushes, these redstarts are now included in the Old World Flycatchers, Muscicapidae. Two weakly differentiated subspecies are recognized. Japanese birds are the slightly paler northern nominate race. Canon PowerShot SX60.
References:
Brazil, Mark (2009): The Birds of East Asia: China, Taiwan, Korea, Japan, and Russia. Princeton University Press. ISBN 0-691-13926-1
Collar, N. (2019). Daurian Redstart (Phoenicurus auroreus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from https://www.hbw.com/node/58501 on 2 April 2019).