In English, people say that an attack on one ally is an attack on all. Chinese paints the same thought with two parts of a face.
The Chinese idiom is 唇亡齿寒, in pinyin *chun wang chi han*. Word for word, it means when the lips are gone, the teeth grow cold. The lips and the teeth are not one thing. They do different work. But the lips stand in front on a cold day, and the teeth feel the loss the moment they are gone.
Like many Chinese proverbs, it is really a small warning about position. It says that two neighbors can be separate countries, with separate names and separate rulers, and still share a single fate. The Chinese call this kind of four-character teaching a chengyu. This one comes from the *Zuo Commentary*, a history of the Spring and Autumn period, and from a warning a minister gave his ruler, and the ruler refused to hear it.
The state of Jin lay in the west. Its ruler, Duke Xian, wanted to grow, and to the south he saw the state of Guo.
Guo was small, but it sat on the road. If Jin wanted to reach the plains of the center, it had to pass that way.
Between Jin and Guo, however, lay the state of Yu.
Yu was small as well. It had little land and few soldiers. What kept it safe was not its army but its place on the map. It was the gate on the southern road, and it was also the back door of Guo. Whoever held that gate had to be handled with care.
Jin could not smash through. It could not walk around. Duke Xian sat with the problem for a long time.
One of his ministers, Xun Xi, had an idea.
The ruler of Yu, he said, is greedy. We have two things he wants. Horses from the Qu pastures, and jade from Chuiji.
Send those, and ask for the road.
Duke Xian winced. He loved those horses. He kept the jade where he could look at it every day.
Xun Xi answered with one plain sentence.
If we send them and get the road, he said, we are only leaving the horses and the jade in Yu for a while. They come back to us in the end.
Duke Xian stared at the horses, and finally nodded.
This was not the first time he had tried it. A few years earlier he had asked for the same road, and the same minister in Yu, a man named Gong Zhiqi, had stood up and objected. The duke of Yu had ignored him then, and Jin had marched through and taken a border town from Guo.
So Gong Zhiqi had already failed to stop this once.
This time, Jin was not asking for a town. It was asking for a whole life.
The envoys carried the horses and the jade into the palace of Yu.
The duke of Yu could not take his eyes off them. He agreed to the road on the spot, and told everyone what good friends Jin was.
Gong Zhiqi stepped forward.
This time he spoke harder.
Guo, he said, is the screen of Yu. Guo and Yu are like a cart and the boards that hold its sides together. Neither stands without the other. They are like the lips and the teeth. Take away the lips, and the teeth grow cold — 唇亡齿寒. If Guo falls today, Yu falls tomorrow.
The duke waved a hand. Jin and I share the same clan, he said. We are both of the surname Ji. Why would Jin harm me?
Gong Zhiqi asked a question back.
Guo also carries the surname Ji, he said. The founders of Guo served the royal house, and earned merit that was written into the records. If Duke Xian will not spare kin like that, why should he spare Yu?
The duke still would not bend.
So Gong Zhiqi pushed harder.
Duke Xian has not spared his own blood, he said. The descendants of Duke Huan and Duke Zhuang, what crime did they commit? Their only fault was that their families were large, and their weight pressed on him. One by one, he removed them. A man who does this to his closest kin, and to kin who served the throne, will he soften for a small neighbor that happens to stand in his road?
The duke changed his argument.
I offer sacrifices, he said. My offerings are generous and clean. The spirits will protect me.
Gong Zhiqi smiled.
The spirits protect virtue, he said. If Jin takes Yu, then Jin can wash up and lay out offerings of its own, finer ones, to the same spirits. Will the spirits still know whose grain was in the dish?
The duke of Yu did not change his mind.
Gong Zhiqi walked out.
He went home, called his clan together, and packed what they could carry. Before he left, he left one sentence behind. Yu will not last until the winter sacrifice, he said. Jin will not need a second campaign.
That winter, the army of Jin marched through Yu.
Guo fell.
Then the army turned around and walked back across Yu.
This time it did not ask for a road.
It used the hospitality of Yu, and the fact that Yu was not on guard. It surrounded the capital. The duke of Yu was still waiting for gifts and thanks. What came through his door was soldiers.
He was taken prisoner.
He was marched west. Duke Xian married his daughter to the Duke of Qin, and the duke of Yu was sent along with the bridal party, as a servant.
The jade came back to Duke Xian. The horses went back to the stables of Jin.
Only the land of Yu changed hands for good. Gong Zhiqi and his clan lived, because they had walked out early.
Jin did not march one extra mile, and it did not spend one extra coin. It used the greed of the duke of Yu, borrowed the road of the duke of Yu, and destroyed the state of the duke of Yu.
The *Zuo Commentary* does not praise Gong Zhiqi without reservation. It calls him timid. He argued, and he could not move his ruler. He could not stop the plan by force, and in the end he only saved his own family. He was right about what would happen. He was not strong enough to prevent it.
That may be the sharpest part of the story. Knowing that the teeth will grow cold is not the same as keeping the lips. It is a Chinese fable in miniature, with no magic and no monsters, only two rulers and one border.
Kings and ministers are gone now, but the shape of the problem is not. Companies sign partnership agreements. Countries join alliances. A small supplier depends on one big customer, and the big customer depends on one market. Everyone tells themselves the same thing the duke of Yu told himself. We are friends. He would not do that to me.
Chinese proverbs like this one rarely ask you to be clever. They ask you to notice where you stand. When your fortunes are tied to a neighbor, a partner, or a country next door, their fall is your weather. The wall they knock down today may be the wall that was keeping the wind off you.
And when your teeth finally feel the cold, the lips are long gone.
