It is a medium-sized raptor (29 to 36 cm) with short broad wings and a long tail, both adaptations to fast maneuvering through dense vegetation.

The adult male besra has dark blue-grey upperparts, and is white, barred reddish brown below.

The besra was formally described and illustrated in 1822 by the Dutch zoologist Coenraad Jacob Temminck based on a specimen collected on the island of Java.

In 2024 a comprehensive molecular phylogenetic study of the Accipitridae confirmed earlier work that had shown that the genus was polyphyletic.

The genus Tachyspiza was resurrected to accommodate the besra together with 26 other species that had previously been placed in Accipiter.