San Ling Wu Shen (Repeated injunctions)
In the Spring and Autumn Period (770-476 BC), the famous strategist Sun Wu (孙武) known as Sun Zi (孙子) came to see the King of the State of Wu, bringing along his great work The Art of War (孙子兵法).
He offered to help turn the State of Wu into a more powerful kingdom by training a strong army for it.The king was not quite convinced and asked, "Can you try your method out on a small army?"
Then, Sun Wu asked these women, "do you know how to march forward, backward, to the left and to the right?"
Now, he beat the drum and gave an order to march to the left. The ladies giggled instead of taking his order. This time, Sun Wu said seriously: "Now the order has been made clear, so that's the leaders' faults not to obey that!" He ordered to behead the two leaders.
The king who was watching the training all the time was shocked and immediately sent someone to plead for mercy for his two concubines. But Sun Wu rejected the pleading. On his insistence, the two-team leaders were executed. Sun Wu appointed two new team leaders and went on with the training. Everybody turned very serious and acted correctly to Sun's orders, just like soldiers.
From then on, the troops of the state of Wu were trained by Sun Wu and became stronger and stronger.
From how Sun Wu repeated his orders comes the idiom "Repeating an order time and again".