ज्येष्ठ-कनिष्ठ-धर्मः — Duties of Elders and Juniors
Anuśāsana-parva 108
प्राडमुख: श्मश्रुकर्माणि कारयेत् सुसमाहित: । उदड्मुखो वा राजेन्द्र तथायुर्विन्दते महत्
prāḍmukhaḥ śmaśrukarmāṇi kārayet susamāhitaḥ | udaṅmukho vā rājendra tathāyur vindate mahat, rājendra |
Bhīṣma said: “O king, a man should have shaving and related grooming rites performed while fully composed, facing either the east or the north. By doing so, O best of kings, he is said to obtain great longevity.”
भीष्म उवाच
Maintain mental composure and follow auspicious orientation (east or north) during personal grooming rites; such disciplined conduct is presented as supportive of health and longevity.
In the Anuśāsana Parva, Bhīṣma continues instructing Yudhiṣṭhira on codes of proper conduct (ācāra). Here he gives a specific rule about the direction one should face while having shaving performed, linking it to the benefit of long life.