Once upon a time, there was a master chess player named Yi Qiu, whose skills were so refined that he decided to teach two students to pass on his art.
When the master chess player Yi Qiu taught, he was meticulous and thorough, laying out every variation of the board and explaining each move and situation with crystal clarity.
Two students studied Go under the same master, Yi Qiu, but their attitudes could not have been more different. One student focused intently, absorbing every word of Yi Qiu's instruction. The other sat through the lesson, but his mind wandered, thinking, "If a swan flies by right now, I'll shoot it down and enjoy a fine meal!"
After class, Yi Qiu had two students play a game of Go to see who had improved more. After politely deferring to each other, they began battling fiercely on the board.
Soon after the match began, the difference in skill became clear. The student who had listened intently moved his pieces with calm composure, exuding confidence and grace. In contrast, the student who had been daydreaming about shooting swans scrambled frantically, barely able to defend himself with no chance to counterattack. Within moments, this lopsided game of Go came to an end.
Yi Qiu saw this and said frankly and sincerely to the student who was fixated on shooting swans, "You two studied together. You are no less intelligent than him, so why is there such a gap in your results? It is because he concentrates wholeheartedly, while your mind is elsewhere!"
Later, people used the idiom "single-minded devotion" to refer to concentrating intently and being highly focused.
Source: *Mencius*, Chapter "Gaozi I"
Meaning of the Idiom: Later, the Chinese idiom "专心致志" came to describe concentrating intently and being highly focused.