Chinese Idiom: 不越雷池一步 (Bu Yue Lei Chi Yi Bu)
English Translation: Not stepping beyond the Thunder Pool
pīn yīn: bù yuè léi chí yī bù
Idiom Meaning: This idiom means not crossing a set boundary or limit. It is often used to emphasize strict adherence to one’s responsibilities or to rules without overstepping. It can also refer to maintaining discipline and not going beyond what is allowed or expected.
Historical Source: Bào Wēn Qiāo Shū (《报温峤书》), a letter by Yu Liang of the Eastern Jin dynasty.
Idiom Story:
During the Eastern Jin dynasty, there was a well-known official named Yu Liang, who was from Yǐngchuān, Yanling (modern-day Yanling County, Henan Province), and his courtesy name was Yuánguī. Yu Liang served in the courts of Emperor Yuan, Emperor Ming, and Emperor Cheng. In August of the year 325 CE, Yu Liang supported the ascension of Emperor Cheng (Sima Yan) to the throne and became the Secretary General of the imperial court, holding significant power over the Eastern Jin dynasty.
Recognizing the threat posed by rebellious forces led by Su Jun and Zu Yue, who were planning to attack the capital, Yu Liang appointed Wen Qiao to defend Jiangzhou (modern-day Jiujiang, Jiangxi Province). Soon after, Su Jun and Zu Yue launched their rebellion and marched on Jiankang (modern-day Nanjing, Jiangsu Province), the imperial capital. Wen Qiao, wishing to aid in quelling the rebellion, planned to lead his troops across the Leishui River (part of which was known as Lei Pool) to join the defense of the capital.
When Yu Liang learned of Wen Qiao’s intentions, he wrote him a letter, advising him not to leave his post. In the letter, Yu Liang expressed his concerns about the western frontier and the importance of Jiangzhou’s defense, urging Wen Qiao to stay put and not to cross the Lei Pool. He wrote, “吾忧西陲，过于历阳，足下无过雷池一步也,” which translates to, “I worry about the western frontier more than Liyang. Please do not take even a single step beyond Lei Pool.”
At that time, the situation was critical, and Yu Liang feared that leaving Jiangzhou defenseless could lead to greater danger. Therefore, he strictly instructed Wen Qiao to remain in his position and not to act rashly by moving his troops.
Eventually, the situation changed, and Yu Liang himself went to Xunyang (modern-day Jiujiang, Jiangxi Province) to join forces with Wen Qiao and Tao Kan, the governor of Jingzhou. Together, they successfully crushed the rebellion led by Su Jun and Zu Yue.
From this historical episode, the idiom “不越雷池一步” emerged, symbolizing the importance of not crossing set boundaries and sticking to one’s duties or limits. It serves as a reminder to respect the rules and not overstep one’s authority or responsibilities.
