Arhopala japonica, the Japanese oakblue, is a butterfly of the Lycaenidae family. It is found in Indochina, Japan, the Ryukyu Islands, the Korean Peninsula and Taiwan. The wingspan is 24–30 mm. The larvae feed on Pasania edulis, Pasania glabra, Quercus acuta, Quercus glauca, Quercus serrata, Quercus stenophylla, Cyclobalanopsis glauca, Cyclobalanopsis gilva and Cyclobalanopsis acuta.