अरिविजिगीष्वोर्भूम्यनन्तरः संहतासंहतयोरनुग्रहसमर्थो निग्रहे चासंहतयोर्मध्यमः ॥ कZ_०६.२.२१ ॥
arivijigīṣvor bhūmyanantaraḥ saṃhatāsaṃhatayor anugrahasamartho nigrahe cāsaṃhatayor madhyamaḥ
The ‘middle king’ (madhyama) is the one whose territory is contiguous to both the enemy and the would-be conqueror; he is capable of favoring either a united or a disunited side, and of restraining a disunited one.
Because adjacency gives immediate leverage—military access, supply routes, and the ability to open or close fronts—making the ruler decisive in outcomes.
It implies exploiting fragmentation: coercion, selective pressure, and deterrence are easier against divided polities than cohesive coalitions.