I shall explain Bhava Bala (the strength of a house), which is ever associated with planetary strength; it is strengthened by the house-lord, the lagna-lord, the paksha-lord and planets situated in kendras.
The strength produced by the lunar phase for the Moon, Jupiter, Venus and the rest is reckoned sixtyfold; whatever remains after deducting it should be understood as the paksha-born strength of the malefic planets.
Verse 3 — Hora Lord's Naisargika Strength
वर्षमासदिनेशानां तिथ्यस्त्रिंशच्छरार्णबाम् । होरेशस्य बलं षष्टिरुक्तं नैसर्गिकं पुरा ॥ १३॥
Distinct strengths belong to the lords of the year, month, day and tithi in due measure; but the strength of the lord of the hora is declared to be sixty — pronounced naisargika (natural strength) since ancient times.
Whatever ayana strength the Sun possesses, exactly that much is called Cheshta Bala for him; and to the extent of the Moon's paksha bala, so much is his Cheshta Bala held to be.
Verse 5 — Motion-Based Cheshta Strength Table
षष्टिर्वक्रगते वीर्य्यमनुबक्रगतैर्दलम् । पादो विकलभुक्तेः स्यात तथा मध्यगतैर्दलम् ॥ २२॥
ṣaṣṭir vakragate vīryam anuvakragater dalam | pādo vikalabhukteḥ syāt tathā madhyagater dalam || 22||
A planet moving in vakra (retrograde) motion has full strength of sixty; in anuvakra motion, half; in vikala motion, a quarter; and in madhya (mean) motion likewise half.
Verse 6 — Cheshta Bala Computation and Six-Fold Bala
bhāgīkṛtaṃ tribhir bhaktaṃ labdhaṃ ceṣṭābalaṃ tv iti | sthānadikkāladṛkceṣṭānisargotthaṃ ca ṣaḍvidham || 25||
Reduced to degrees and divided by three, the resulting figure is known as Cheshta Bala; thus the six kinds of strength arise — Sthana, Dik, Kala, Drik, Cheshta and Naisargika.
khāgnayaś ca kramāt sthānadikceṣṭāsamayā'yane | sitendvos tryagnicandrāś ca kheṣavo khāgnayaḥ śatam || 35||
The numerical weights to be applied in order to Sthana, Dik, Cheshta, Kala and Ayana Balas are given through these traditional number-terms — by the Kha-Agni count for Venus and the Moon, and the three-Agni and Chandra figures for the rest — the whole reckoning amounting to one hundred.