Di, the Root, is the third of the twenty-eight xiu and the third mansion of the eastern palace, the Azure Dragon. Its name is read as the root or base, sometimes the dragon's chest or foundation, identified with stars in Libra. In the later astrological tradition its animal totem is the Badger. As one of the twenty-eight lunar mansions it marks a segment of the sky along which the Moon's nightly position is tracked. These are the conventions of the Chinese astronomical and calendrical tradition, in which the twenty-eight xiu, grouped into the four palaces of the Azure Dragon, Black Tortoise, White Tiger, and Vermilion Bird, divide the heavens and underlie the almanac's assignment of auspicious and inauspicious days to the mansion the Moon occupies.
The Badger totem assigned to Di belongs to a set of twenty-eight animals that repeat in groups of four across the full cycle, each group of four sharing one of the seven classical Chinese "planets," the sun, moon and five visible planets, an arrangement also credited with giving East Asia its seven-day week, since the same seven bodies cycling through the mansions in fixed order supplied the sequence later adopted for the days themselves, still visible today in the Japanese weekday names for Sun, Moon, Fire, Water, Wood, Metal and Earth.