during the late years of the qi dynasty(221-206bc), xiang yu led a rebellion1. after crossing the zhang river, xiang yu ordered his men to sink all their boats and break their cooking pots. he issued each soldier three days' rations2（给养） and warned them that there was no way to retreat3; the only thing they could do to survive was to advance and fight. after mine fierce battles, the qin army was finally defeated.
this idiom is used to indicate one's firm determination to achi* one's goal at any cost.
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