Once upon a time, there was a man named Guo Han.
One summer evening, Guo Han was cooling off outdoors
He thought of the legendary Chang'e flying to the moon, and the Cowherd and the Weaver Girl: Where is Chang'e now? The colorful clouds in the sky must surely be the Weaver Girl's masterpiece. The Weaver Girl is more industrious than Chang'e, weaving day and night without rest, creating a tapestry of splendor across the heavens; in comparison, she is more worthy of praise than Chang'e.
As Guo Han stood stunned, the moon slipped behind the clouds, and the clouds took on a wondrous hue. Lost in reverie, he suddenly saw a colorful cloud transform into a celestial maiden, who quietly descended from the sky.
Guo Han thought he was still dreaming when the fairy maiden appeared before him. Seeing her radiant beauty, he quickly bowed and asked if she was a celestial maiden. The fairy maiden returned the greeting and replied, "I am the Weaver Girl from heaven!"
Upon hearing that she was the Weaving Maiden, Guo Han was both astonished and delighted, and he took a closer look. He saw that her clothes were extraordinarily beautiful, dazzlingly bright, and utterly unlike anything in the mortal world. Even stranger, her garment had not a single seam. He asked her, "Immortal Lady, your dress has no seams to be found—what fabric is it made from, and how was it sewn?"
The Weaving Maiden smiled and replied, "This is a heavenly robe, which naturally requires no needle and thread to sew!" "Truly seamless heavenly garments!" Guo Han couldn't help but exclaim repeatedly. Later, people used the idiom "seamless heavenly robe" to describe things that are perfectly natural, meticulously thorough, and without any flaw to be found.
Source: Niu Qiao (Former Shu Dynasty), *Records of Strange Tales*, "Guo Han"
Meaning of the Idiom: Later, the Chinese idiom "天衣无缝" came to describe things that are perfectly natural, meticulously thorough, and without any flaw to be found.