Stratagem No. 20 第二十计 Chaos stratagems (混战计)
Fish in troubled water
Literal
In muddy water, grope for fish.
When the other side is disordered and nobody is truly in charge, move quietly and take what their confusion has left loose.
Source line
乘其阴乱，利其弱而无主。随，以向晦入宴息。
Traditional 乘其陰亂，利其弱而無主。隨，以向晦入宴息。
Exploit their hidden disorder, and profit where they are weak and have no master. The hexagram Sui (Following): as evening comes, go in and rest.
Icons working translation — draft, pending review
Sui (Following) is thunder under the lake, and its Image has the superior man go in to rest at evening. Here the dusk is a leaderless muddle: you do not clarify it, you move with it and take what no one is holding.
三十六计 · Chinese Wikisource edition (public domain)
Meaning
Fish in troubled water means you take advantage of a side that is already disordered, weak, and without a real master. The mud is not something you have to stir. It is already there: factions, a frightened court, a host who cannot decide. In that dusk the commentary says the weak lean one way and then the other, scatter, and fail to see. You go in with them, quietly, and you come out holding what they dropped.
This is narrower than ordinary opportunism. The classical line asks for two conditions, hidden disorder and the lack of a master. A busy but well-led enemy is not this pool. The Six Secret Teachings, which the commentary quotes, lists the signs: an army that startles often, soldiers who frighten one another with talk of the enemy’s strength, rumours that will not stop, orders that no longer bite, a general no one respects. Those are fish. You choose them. You do not fight the whole river.
The story
Liu Bei enters Yi province, 211–214 刘备入蜀
History
In 211 Liu Zhang, governor of Yi province, was afraid of Zhang Lu to his north and listened to men who said Liu Bei would be a useful ally. He invited Liu Bei in, met him at Fu, feasted him for weeks, gave him troops and supplies, and pointed him at the northern front. People on Liu Zhang’s own side could see the water. Yan Yan, holding Ba commandery, is recorded as sighing that his master sat in the mountains and had hired a tiger to guard him. Liu Zhang was the host, and he did not have a firm hand on his own court.
Liu Bei did not have to invent the trouble. He entered as a guest, took the gifts, and waited while Zhang’s officers split between those who wanted him and those who feared him. In 212 the joint war against Zhang Lu came apart. Liu Bei turned on the man who had invited him. Pang Tong, who had argued for speed, was killed in the fighting at Luo city. Liu Bei kept the siege. In 214 Zhuge Liang, Zhang Fei and Zhao Yun came up the Yangtze, Guan Yu staying behind in Jing province, and Chengdu surrendered. The guest had arrived to help. He left owning the house.
The stratagem commentary also claims Liu Bei’s gain in Jing province for this trick. That story is real and messier. After Red Cliffs in 208 he held much of the south of Jing, while the key commandery was disputed with Sun Quan’s general Zhou Yu, and the later slogan about borrowing Jingzhou flattens a quarrel the two allies never told the same way. The Yi campaign is the clean specimen: a weak host, a cloudy court, an invited ally who stayed.
The invitation, the break, and the fall of Chengdu in 214 are in Chen Shou’s Sanguozhi, Yan Yan’s remark is the traditional telling of his protest, and the novel’s tale of borrowed Jingzhou should not be read back onto 211.
Sources
- Chen Shou, Sanguozhi 三国志, Shu shu, biographies of Liu Bei and Liu Zhang
- Sima Guang, Zizhi tongjian 资治通鉴
Myth check
The English proverb already means profiting from confusion, but this entry is stricter: the other side must be disordered and leaderless, and a busy market is not enough. Liu Bei’s campaign in Yi is history, the flat tale of borrowing Jingzhou is a later simplification, and the line is not in Sun Tzu.
Modern application
In a merger or a joint bid, watch the partner whose own people cannot agree who decides. The invitation to ‘help with one problem’ is the Fu meeting: troops, budget, and a badge at the door. If their deputies brief you against each other, you are already in the pool. The disciplined move is to see that early, and either leave or, if the work is really yours to take, stop pretending it is still their project.
Politics produces the same water whenever a coalition keeps its label and loses its leader. Committees, clubs, and family firms all do it. The person who drafts the minutes, holds the keys, and talks to the frightened middle often ends with the organisation, while the nominal head is still hosting the dinner. Muddy is not the same as evil. It means no one is steering.
Takeaways
- Enter only where no one is truly in charge.
- Read rival briefings as a map of the mud.
- Do not stir a pool that already has a master.
How to counter it
A guest who asks for a narrow brief, then starts to be briefed by your own unhappy people, is fishing. Keep one decision-maker, put the terms of help in writing, and do not hand over troops, keys, or the customer list ‘for the duration’.
Questions
What does fish in troubled water mean in the 36 stratagems?
It means taking what you want from a side that is already confused, weak, and without a real leader. You move with their disorder instead of clarifying it. The classical line borrows the hexagram Following: at evening, go in and rest. The test is leaderlessness. A strong opponent who is merely busy does not qualify.
Did Liu Bei steal Jingzhou by this stratagem?
The stratagem commentary claims both his gain in Jing and his taking of Yi province. Yi, from the invitation of 211 to the fall of Chengdu in 214, is the clear case in Chen Shou. Jing is a real dispute with Sun Quan after 208, later flattened into a story of borrowing. Treat that slogan as legend laid over a messier alliance.