[609] And how is a bhikkhu devoted to the practice of wakefulness (jāgariyānuyoga) in the earlier and later parts of the night?
Here a bhikkhu, during the day, purifies his mind (citta) of obstructive phenomena (āvaraṇiyā dhammā) by walking back and forth (caṅkama) and by sitting. During the first watch of the night he purifies his mind of obstructive phenomena by walking back and forth and by sitting. During the middle watch of the night he lies down on his right side in the lion's posture (sīhaseyyā), placing one foot upon the other, mindful (sato) and clearly comprehending (sampajāno), having attended to the perception of rising (uṭṭhānasaññā). During the last watch of the night, having risen, he purifies his mind of obstructive phenomena by walking back and forth and by sitting. Thus a bhikkhu is devoted to the practice of wakefulness in the earlier and later parts of the night.
English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.