The symbol is the Chinese character for "double happiness," (song hi in Vietnamese) and (shuangxi in Chinese). Wang Anshi (1021-1086), a famous Chinese politician during the Song Dynasty, created the symbol. When he was twenty, Wang Anshi traveled to the capital to sit the royal exams. During his journey, as he passed through a small town, he saw a sentence written on a paper banner that hung from a lantern near a house gate. A decorative revolving screen inside the lantern cast shadows on the lamp shade. The banner read, "The lantern of the pulling horses: The horses gallop when the lamp bums but halt when the lamp is snuffed."

Wang realised that the house owner, a landlord named Ma (Horse), was inviting passers-by to create a pair of perfect parallel sentences by writing a second sentence to match. Smiling, Wang said to himself, "It's so simple!"