Here is a quick guide to distinguishing the subspecies, gleaned from Klaus-Dieter Schulz's A Monograph of the Colubrid Snakes of the Genus Elaphe Fitzinger (1996, Koeltz Scientific, Czech Republic).

The key characteristic is the dorsal pattern on the front half of the snake.

E. t. taeniura - this subspecies is found in Eastern China. The dorsal pattern (looking from directly above) is ladder-like.

E. t. yunnanensis - this subspecies has a wide range, from Burma, China, India, Laos, Thailand, and Vietnam. The dorsal pattern is made up of crossbars or X's.

E. t. friesi - this is the true Taiwan subspecies. The dorsal pattern is 2 rows of strong blotches, which gradually become ladderlike.

E. t. mocquardi - this subspecies is found in southern China and northern Vietnam. The dorsal pattern shows 2 rows of thin blotches, which may be connected to each other (in the same row) with thin lines.

E. t. schmackeri - this subspecies is found in the Japanese Ryu-kyu's. The dorsal pattern is made up of very indistinct blotches. A second characteristic is that the usually strong "eye patch" is very indistinct in this subspecies.

E. t. grabowski - this subspecies is found in Borneo and Sumatra. There is no strong pattern against the dark background, and lacks strong striping throughout the body.

E. t. ridleyi - this subspecies is found in peninsular Malaysia. There are crisp stripes along the body with no interfering patterns.