पक्षौ कक्षाव् उरस्य्म् प्रतिग्रह इति बार्हस्प्त्यः ॥ कZ_१०.६.०२ ॥
pakṣau kakṣāv urasym pratigraha iti bārhaspatyaḥ
According to Bārhaspatya, (the array consists of) the two wings (pakṣa), the two ‘kakṣā’ (guarding side-belts/auxiliary flanks), the centre (urasya), and the reserve (pratigraha).
Bārhaspatya adds ‘kakṣā’ as an intermediate protective layer, implying greater depth and side-security beyond simple wing-and-centre.