यद्वा परस्य सारिष्ठं तद्द्विगुणसारेणाभिहन्यात् ॥ कZ_१०.५.५० ॥
yadvā parasya sāriṣṭhaṃ taddviguṇasāreṇābhihanyāt
Or, if it is the enemy’s strongest element, he should strike it with double the strength/resources.
Do not meet it evenly; apply at least a twofold advantage to break it decisively.