Wu · Horse

Meaning

Wu 午 is the seventh Earthly Branch: the branch of the Horse, of the south, of the double hour around noon and of the fifth month of the Chinese year, the one that holds the summer solstice. It is Fire at its height and, in the cycle, yang: the brightest point of the year, which is also the point where the light begins to shorten. The Han historians read its name as 啎 wǔ, to go against: in the fifth month, Xu Shen wrote, yin rises against yang and pushes up through the ground. Wu is the mirror of Zi across the circle: where midnight holds the first yang, noon holds the first yin.

It is read as warmth, enthusiasm and openness, the Horse’s love of movement and company, a frank and generous energy that is visible from afar, the joy of a summer day. Wu wants to go, to meet, to say. Its difficulty is the noon sun’s: a heat that can exhaust itself, impatience with what does not move as fast, and a restlessness that leaves things half done when the next road calls.

As one of the four cardinal branches, with Zi, Mao and You, Wu is the heart of its season and the peak of the Fire trine. It is the only one of the four to hold two stems: Ding, yin Fire, its main qi, and Ji, yin Earth, the ground that summer’s heat ripens.

In practice

• In BaZi, Wu holds Ding as its main qi, with Ji. It is the Prosperity of Ding and Ji and the Peak of Bing and Wu 戊, which makes it the Sword Edge of both, the Nobleman of Xin and the Academic star of Yi. A Wu month, from Mangzhong, about 6 June, to Xiaoshu, about 7 July, is the height of summer: Fire at its strongest, Water at its weakest, which is why Ulune’s climate view suggests Water for summer charts.
• Its relations: Wu is in harmony with Wei, a pair that leans towards Fire, or Earth in some books; it is the peak of the Fire trine with Yin and Xu, and the middle of the summer trio with Si and Wei. It clashes with Zi, the other pivot of the year, harms Chou, forms a destruction with Mao, and punishes itself when it meets itself.
• In Chinese astrology, Wu is the Horse: 2026 is the year of the Fire Horse, Bing-Wu, from Lichun 2026 to Lichun 2027; 2014 was a Wood Horse year and 2038 will be an Earth Horse year.
• In Feng Shui, Wu is the middle mountain of the south, from 172.5° to 187.5°, a yin one for the Flying Stars; in a Horse year Tai Sui sits there, and the year breaker opposite, at Zi.

Across traditions

• In Japan the branch is read uma, the horse; in Korea o; in Vietnam Ngọ. Chinese and Japanese still say the hours before and after noon as 午前 and 午後, “before Wu” and “after Wu”, and the Dragon Boat Festival, on the fifth day of the fifth month, is 端午 Duānwǔ, the opening of Wu.
• The Yi Jing’s sovereign hexagram for the Wu month is Coming to Meet (Gou, the 44th): one broken line beneath five whole ones, the first yin returning at the height of yang.
• Western astrology begins Cancer at the summer solstice, which falls in the middle of the Wu month; it gives the longest day to a water sign, as China gives it the first yin.

Origin and history

Wu is one of the branch characters of the Shang oracle bones, where it is drawn as a pestle, a shape the later 杵 keeps. The Huainanzi (139 BC) sets it at the south and at midsummer; Sima Qian wrote that in Wu yin and yang cross, and Ban Gu that things spread out in Wu; Xu Shen’s Shuowen Jiezi (c. 100) speaks of yin rising against yang in the fifth month. The north–south line of every Chinese compass, from Zi to Wu, became the 子午線, the meridian.

BaZi’s classics read Wu as the strongest Fire among the branches, and the Fire trine of Yin, Wu and Xu as the birth, the height and the storehouse of Fire, as the Huainanzi already describes the three branches of each phase. Whether the harmony of Wu and Wei makes Fire or Earth has been read both ways in BaZi’s books; Ulune follows the books that make it Fire and says that others make it Earth.

How Ulune calculates it

Ulune numbers Wu 6 among the branches. The Wu month runs from the exact moment of Mangzhong, the Sun at 75°, to Xiaoshu, the Sun at 105°, and holds Xiazhi, the summer solstice, at 90°; the Wu hour is 11:00 to 13:00 on true solar time at the birthplace by default, which puts true noon at its middle. In BaZi’s balance its hidden stems count 0.7 for Ding and 0.3 for Ji, twice in the month branch. Wu is one of the four branches Ulune reads as punishing themselves, with Chen, You and Hai; and for a year or day branch of the Si, You and Chou trine it is the Peach Blossom, for one of its own trine the General.

Correspondences