These are two different winter females. Note gray lesser coverts. Sometimes called "Elegant Bunting" we encountered this species only once. It is an uncommon winter visitor to Japan. These are the more widespread nominate race. It is widely separated from a darker, more heavily marked population in central China. Canon PowerShot SX60.
References:
Byers, C., J. Curson, and U. Olsson. 1995. Sparrows and Buntings: A Guide to the Sparrows and Buntings of North America and the World. Houghton Mifflin, Boston.
Copete, J.L. (2019). Yellow-throated Bunting (Emberiza elegans). 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/61885 on 18 May 2019).