This is an immature showing mostly dark head and white collar. The patches of white on its head, back and lesser wing coverts indicate molting and photos indicate that it has begun wing molt with p1 and p2 growing in. This individual kept its bill partly open most of the time. This species is an uncommon visitor to Japanese waters, more common southward with most sightings far offshore. Light eyed birds in the Western Pacific are included in the medium sized subspecies S. d. personata. Species formerly went by the English name, Blue-faced Booby. Canon PowerShot SX60 HS.
References:
Brazil, M.A. (1991) The Birds of Japan. Smithsonian Inst. Press.
Brazil, M. (2009) Birds of East Asia. Princeton Univ. Press.
Carboneras, C., Christie, D.A., Jutglar, F., Garcia, E.F.J. & Kirwan, G.M. (2019). Masked Booby (Sula dactylatra). 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/52623 on 5 October 2019).
Marchant, S. & Higgins, P.J. (co-ordinating editors) 1990. Handbook of Australian, New Zealand & Antarctic Birds. Volume 1, Ratites to ducks; Part B, Australian pelican to ducks. Melbourne, Oxford University Press. Pages 737, 748, 763-772; plates 56 & 58.