Xin (Heart)

Xin (Heart) is the fifth of the twenty-eight xiu, the lunar mansions of traditional Chinese astronomy. Each xiu is a segment of the sky marked by a group of stars near the celestial equator, and together they divide the heavens into the belt through which the sun, moon and planets appear to move.

Palace, animal and place in the sky

This mansion belongs to the Azure Dragon of the East, the quadrant of the sky lying toward the east, one of the four symbolic creatures among which the twenty-eight are shared out seven to each. In the later scheme that pairs every mansion with a creature, Xin is assigned the Fox.

The twenty-eight mansions are among the oldest elements of Chinese sky-lore, attested well before the common era and used to track the nightly progress of the moon and to fix the calendar. The system is described here as that documented astronomical and calendrical tradition, from which its astrological uses later grew.

Xin, the Heart, is the fifth of the twenty-eight xiu and the fifth mansion of the eastern palace, the Azure Dragon. Its name means the heart, and it is identified with the red star Antares in Scorpius, known in Chinese astronomy as the Fire Star, at the very heart of the dragon. In the later astrological tradition its animal totem is the Fox. Antares was a key seasonal marker in ancient China, its evening position watched to regulate the calendar. As one of the twenty-eight lunar mansions Xin tracks a segment of the Moon's path. These are the conventions of the Chinese astronomical and calendrical tradition, in which the twenty-eight xiu order the sky into four great symbolic animals, each spanning a quarter of the heavens.

The Shang dynasty oracle bones that record Xin's heliacal rising, dated to roughly the thirteenth century BCE, make it one of the earliest individually named and tracked stars in any surviving written record worldwide, predating by many centuries the Babylonian star catalogues usually cited as the oldest systematic stellar records in the Near East. The same inscriptions include what many historians of astronomy consider the earliest surviving record of a nova, a "new star" reported appearing near Antares, underscoring how closely this particular mansion was watched.