The custom of “Writing the Nine-Day Periods” appeared in the early reign of Emperor Daoguan in the early 19th century. He drew a picture of the nine-day periods by himself with a line on it, “The willow in the front yard respectfully waits for he spring breeze to return.” The line comprised nine contoured Chinese characters, each with nine strokes “亭前垂柳珍重待春风”.

He then asked the officials to fill each stroke on a daily base and write down the weather conditions at the same time. Later on, this method became popular too and many classic poem came out. Some people created couplets, in which there were nine characters in each line and nine strokes in each character. The couplets were to be filled in the same way in winter and were called “the Nine-Day Couplets Welcoming the Spring”.