To stick to the established rule

King Chu Jing asked Gong Shu-ban to design scaling ladders for attacking walled cities. He was preparing to attack the State of Song.

When Mo Di, came to know about King Chu's plan, he journeyed for 10 days to the State of Chu to pay a courtesy call on King Chu. He told King Chu, "The State of Chu has a large and fertile land whereas the State of Song is only a small country. I understand that you want to attack the State of Song. Are you not opening yourself to criticism by others ?"

King Chu replied, "While this may be true, Gong Shu-ban has designed the scaling ladders. I must conquer the State of Song."

Mo Di then asked Gong Shu-ban to play with him the game of the simulated battle. Mo Di took his belt to represent the city's wall in the game. Chopsticks were used to represent the weapons. Gong Shu-ban mobilized the models of his scaling ladders for the attack but for nine times he was beaten off. Upon seeing this, King Chu gave up the plan to attack the State of Song.

Today, this idiom is used to describe one's old idea without change to progress.