Acanthurus japonicus was first formally described as Hepatus aliala japonicus in 1931 by the Soviet ichthyologist Peter Yulevich Schmidt with its type locality given as Kominato on Amami-Oshima in the Ryukyu Islands of southern Japan.

[4] Acanthurus japonicus has a laterally compressed oval body with long based dorsal and anal fins.

[2] The colour of this fish varies with the emotional state of the fish and may be brown, diffused with blue through to almost yellow but its most notable feature is a wide white band extending from the lower part of the orbit to the upper lip.

[5] This species has a maximum published total length 21 cm (8.3 in).

[2] Acanthurus japonicus is found in the Western Pacific Ocean from southern Japan south to Sulawesi in Indonesia.