अनेनैवोपायेन नान्येन इति नियोगः ॥ कZ_०९.७.७४ ॥
anenaivopāyena nānyena iti niyogaḥ
‘By this means alone, and not by another’—this is fixed prescription (niyoga).
When the situation has a clear best instrument and deviation increases risk—policy is mandated rather than discretionary.