《汉书·传·赵充国辛庆忌传》
先零羌被诛杀后罕羌、开羌仍不臣服，等到正月再去攻打它，既得用兵的道理，又合用兵的时机。
先零已诛而罕、开不服，涉正月击之得计之理，又其时也。
After the Xianling Qiang were killed, Xianqiang and Kaiqiang still did not submit. We should wait until the first month to attack it again, using the rationale of using troops and also matching the timing of using troops.