Shloka 23
कृतयुगवर्णनम् तथा राजधर्मोपदेशः
Kṛtayuga Description and Instruction on Royal Dharma
तस्य तावच्छती संध्या संध्यांशक्ष तथाविध: । चार हजार दिव्य वर्षोका एक सत्ययुग बताया गया है, उतने ही सौ वर्ष उसकी संध्या और संध्यांशके होते हैं (इस प्रकार कुल अड़तालीस सौ दिव्य वर्ष सत्ययुगके हैं) ।। २२३ || त्रीणि वर्षसहस्राणि त्रेतायुगमिहोच्यते
tasya tāvacchatī sandhyā sandhyāṁśaś ca tathāvidhaḥ | catvāri sahasrāṇi divya-varṣāṇi ekaṁ satya-yugam ucyate, utāni eva śata-varṣāṇi tasya sandhyā-sandhyāṁśayoḥ (evaṁ kulaṁ catuḥśatāṣṭaśatāni divya-varṣāṇi satya-yugasya) || trīṇi varṣa-sahasrāṇi tretā-yugam iha ucyate ||
Vaiśaṃpāyana said: “The twilight (sandhyā) of that age lasts for a hundred (divine) years, and its concluding twilight (sandhyāṃśa) is of the same measure. Thus, four thousand divine years are declared to constitute one Satya Yuga, with an additional hundred divine years each for its opening and closing junctions—making a total of forty-eight hundred divine years for the Satya Yuga. Thereafter, three thousand divine years are here stated to be the duration of the Tretā Yuga.”
वैशम्पायन उवाच
Educational Q&A
The passage teaches the traditional Purāṇic/Mahābhārata framework of cosmic time: each yuga has a main span plus transitional junctions (sandhyā and sandhyāṃśa). Satya Yuga is defined as 4000 divine years plus 100+100 for its junctions, and Tretā Yuga is introduced as 3000 divine years, implying a graded decrease across ages.
Vaiśaṃpāyana is explaining to his listener the measured durations of the world-ages (yugas). He completes the calculation for Satya Yuga by adding its opening and closing junction periods, then begins stating the duration of the next age, Tretā Yuga.