In the sixth century during the South and North Dynasties period, there lived a man named Chang Sun-ch'eng. He was exceptionally clever and intelligent, and particularly astute at archery.
When Chang and a group of people were sent by the Emperor Chou Hsuan on a mission to visit the Turks in the northwest, he alone won the praise and high regard of the Turkish king. One day, Chang accompanied the king on a hunting outing. Suddenly he spotted two birds fighting for a single piece of meat. "Watch this!" he shouted, and with a single arrow killed both birds.
Thus the idiom, "One arrow, two birds" became a metaphor for receiving two benefits from a single labor.
(Jill Ardourel)