Measuring up to 38 cm (15 in) in total length,[2] it is slightly larger than its close relative the Eurasian jay, with a proportionately stouter bill and also a longer tail.

It has no discernible crest, with the head feathers a velvety black, the shoulders and back a deep purplish blue and all other parts a rich chestnut purple.

This jay has a very restricted distribution occurring only on the southern Japanese islands of Amami Ōshima and Tokunoshima in pine forest, sub-tropical woodland and cultivated areas especially around villages.

Food is largely made up of the nuts of the native chinkapin Castanopsis cuspidata but includes small reptiles and invertebrates of many types.

Today it is threatened by introduced small Indian mongooses, which were brought to its range to control the venomous Okinawa pit viper.