To release a dangerous person or force, allowing them to escape and cause future trouble; to set a fox to guard the hens.
对于那些已经表现出明显不良意图的人，如果不采取措施，反而任其发展，无异于放虎归山，将来必生大患。
For those who have already shown clear malicious intentions, if no measures are taken and they are instead allowed to grow, it's tantamount to letting the tiger return to the mountains, which will surely lead to great trouble in the future.
Era:
Ancient
Frequency:
Synonym:
Story:
During the late Eastern Han Dynasty, Liu Bei found himself in a difficult position and sought refuge with Cao Cao. Cao Cao's strategist, Cheng Yu, knew that Liu Bei was no ordinary man and advised Cao Cao to eliminate him as soon as possible.
To allay Cao Cao's suspicions, Liu Bei pretended to be interested only in gardening and stayed out of political affairs.
After Cao Cao defeated Lu Bu, Liu Bei requested to lead troops to attack Yuan Shu. Cao Cao granted him 50,000 soldiers. Liu Bei then left Cao Cao and established his own independent force.
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