The Horse is paired with wu, the seventh earthly branch, whose double-hour runs from eleven in the morning to one in the afternoon, the hour of noon, and whose phase is fire. It stands exactly opposite the Rat at midnight, the two poles of the daily and yearly cycle. The horse in Chinese culture is the animal of the frontier, of cavalry and of the tribute trade with the steppe peoples, and it carries associations of speed, freedom, martial vigour and travel. The Heavenly Horses of Ferghana, sought by the Han emperor Wu, entered legend as horses that sweated blood, and horse imagery runs through Chinese painting and poetry as an emblem of untamed energy. The traits given to the sign, independence, enthusiasm, restlessness and a dislike of confinement, follow from that.
Beyond the Ferghana horses sought by Emperor Wu, the wider Silk Road trade in horses from Central Asian steppe peoples remained a strategic Chinese state concern for most of the imperial period, since China's own pasturelands were poorly suited to breeding cavalry mounts in the numbers its armies required, making the horse one of the few animals of the cycle whose symbolic prestige was matched by a genuine, centuries-long logistical dependency on foreign supply that Chinese governments actively managed through treaty, trade and, at times, war.