in the warring states period, the state of qin besieged1（被包围，被困扰） the capital of the state of zhao. duke pingyuan of zhao planned to ask the ruler of the state of chu personally for assistance. he wanted to select a capable man to go with him. a man called mao sui volunteered. when the negoti-actions between the two states were stalled（失速的） because the ruler of chu hesitated to send troops, mao sui approached him, brandishing2（挥舞，炫耀） a sword. at that, the ruler of chu agreed to * zhao, against qin.
this idiom means to recommend oneself.
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