Some chinese mirrors are known, because of certain designs with which they are ornamented and which suggest the capital letters T.L.V., as 'T.L.V. mirrors'. These have been considered as sundials, which they are not. They are mandala schemes of the universe - round heaven, the pole star or axis mundi in the middle; square earth; the four gates of the Chung-kuo of china or of the royal palace correlated with the axis mundi. The graphic representation of the schemes of the universe which are made in this manner serve, none the less, a magic end, that of Return, of Unification with the central point from which, as soon as it has been attained, is derived the omnipotence of him who has achieved this. The Tao - first principle and Prime Mover of all things (see Karlgren: Early Chinese Mirror Inscriptions, p. 31, in the Bulletin of the Museum of Far Eastern Antiquities, No. 6 (Stockholm, 1934)) - is identified with the centre and unity: 'May your eight sons and nine grandsons,' reads the inscription on one of these mirrors, 'govern the centre'; that is, may they unite themselves with the Supreme Mover, source of immortality and of thaumaturgical power. The grandsons are nine because nine it the perfect number; specifically four females, even number, Yin, the female principle, the moon; and five males, odd number, Yang, male principle, the sun (cf Karlgren, p. 43). Elsewhere, ibid., page 29: 'If you ascend the (mountain) T'ai-shan, you will see the divine men; they eat the essence of jade and drink the limpid spring; the have attained the Way of Heaven; all things are in their natural state; they yoke the Hornless Dragon to their chariot; they mount the floating clouds; may you have office and rank, may you preserve your sons and grandsons.'
Giuseppe Tucci - The Theory and Practice of the Mandala - Rider & Company - London - 1961.