Thus we read that ‘on the day of full moon Ānanda purified himself, and went up to the upper story of his house to keep the sacred day’ (Mahāsudassana-sutra, 1-10). This was in conformity with the ancient Brāhmanical rule that every new-moon day (Darṡa) and every full-moon day (Paurṇamāsa) should be set apart for special religious observances[156]. In later times the intermediate quarter-moon days were also held sacred, and so the number of Uposatha days (see p. 84) was increased to four in every month, or once a week. Very strict Buddhists in Tibet eat nothing on these days between sunrise and sunset except farinaceous food with tea (p. 346). The laity are invited to join in keeping the Uposatha days, but take no real part in the detail of the services. The same rule applies to all religious ceremonies. Laymen may be present at any rite, but without co-operating in carrying out the ritual. Still, laymen have their own part to perform. They look on—listen, tell their rosaries, and repeat short prayers—such as the ‘three-refuge’ and ‘jewel-lotus’ formula (pp. 78, 370)—and make declarations to avoid the five great sins (p. 126). Or they walk up to the image-altar and place offerings on it, or bow before it and receive the Lāma’s benediction. Theoretically, the laity only exist to honour and support the monkhood, and to be blessed by them in return. At all events a layman’s religion is usually restricted to a very limited range of duty. One common way of showing piety is by walking round temples, monasteries, Stūpas, and sacred walls (see pp. 380, 505), from east to west, keeping the right shoulder towards them, and even occasionally measuring the ground with the extended body.