What is the 5-Period (Wu Yun) and
6-Qi (Liu Qi) Theory?
Found in Chapters 66 through 74 of the Huang Di Nei Jing Su Wen, the Wu Yun Liu Qi theory is a recorded system that gives us insight into the qi energies present at any given time.
What is the Wu Yun?
​The ancient sages observed the sky and paid attention to the positions of the North Star, the Big Dipper, the sun, and the moon. Over time, they determined that there are five distinct periods in both the sky and on Earth for any given year. The sky was divided into the four directions — east, west, north, and south — and the center, the pole star.
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Each direction was associated with a specific qi, known as YunQi. In the sky (universe), these are:
Wind, Fire, Dampness, Dryness, and Cold
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On Earth, they correspond to:
Wood, Fire, Earth, Metal, and Water
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These also align with the seasons: spring, summer, late summer, fall, and winter.
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This cosmological understanding led to the creation of the 60-year Sexagenary Calendar, in which each year is influenced by a specific YunQi that affects weather patterns and all living beings. Each YunQi is connected to one of the 10 Celestial Stems, which cycle every 10 years.
The 10-Year Celestial Stem Cycle
Year Stem
YunQi
Calendar Years
Jia
Excess (Yang) Earth
1944, 54, 64, 74, 84, 94, 2004, 14, 24
Yi
Deficient (Yin) Metal
1945, 55, 65, 75, 85, 95, 2005, 15, 25
Bing
Excess (Yang) Water
1946, 56, 66, 76, 86, 96, 2006, 16, 26
Ding
Deficient (Yin) Wood
1947, 57, 67, 77, 87, 97, 2007, 17, 27
Wu
Excess (Yang) Fire
1948, 58, 68, 78, 88, 98, 2008, 18, 28
Ji
Deficient (Yin) Earth
1949, 59, 69, 79, 89, 99, 2009, 19, 29
Geng
Excess (Yang) Metal
1950, 60, 70, 80, 90, 2000, 10, 20, 30
Xin
Deficient (Yin) Water
1951, 61, 71, 81, 91, 2001, 11, 21, 31
Ren
Excess (Yang) Wood
1952, 62, 72, 82, 92, 2002, 12, 22, 32
Gui
Deficient (Yin) Fire
1953, 63, 73, 83, 93, 2003, 13, 23, 33
What is the Liu Qi?
The Liu Qi, or Six Qi, describe six energetic patterns observed both in the cosmos (as climatic factors) and on Earth (as seasonal phases):
LiuQi
Characteristics
Season
Jueyin
Wind, Wood
Spring
Shaoyin
Imperial Fire
Summer
Shaoyang
Ministerial Fire
Summer Heat
Taiyin
Dampness, Earth
Late Summer
Yangming
Dryness, Metal
Autumn
Taiyang
Cold, Water
Winter
The Liu Qi & Earthly Branches
Each year is also associated with one of the 12 Earthly Branches, often represented by the zodiac animals. These connect with the Liu Qi as follows:
Branch (Zodiac)
LiuQi
Zi (Rat)
Shaoyin
Chou (Ox)
Taiyin
Yin (Tiger)
Shaoyang
Mao (Rabbit)
Yangming
Chen (Dragon)
Taiyang
Si (Snake)
Jueyin
Wu (Horse)
Shaoyin
Wei (Goat)
Taiyin
Shen (Monkey)
Shaoyang
You (Rooster)
Yangming
Xu (Dog)
Taiyin
Hai (Pig)
Jueyin
The energies of the Celestial Stem and the Earthly Branch combine each year to create qi characteristics that are found in Earths climatic patterns and mirrored in all living beings. For example, the upcoming Celestial Stem for 2025 is Yi and the Yun Qi for the year is Deficient Metal. By studying the Huang Di nei jing su wen we learn there are specific climatic and health characteristics inherent in years ruled by the Yun Qi of Deficient Metal. Another layer of characteristics is added when the qi of the Earthly Branch for the year is considered. In 2025 the Earthly Branch is Si (Snake) and the Liu Qi is Jueyin (Wind).
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As practitioners and students of East Asian Medicine we can apply this understanding of qi cycles to our treatment strategies and protocols in clinical practice.
The 2025 Annual Qi Datebook
is Now Available
This datebook includes the moon phases, the 24 Solar Terms, the Six Qi periods for 2025, and the essential rhythms and energies that significantly influence various aspects of our lives. Integrating these elements into your planning can help you align your daily activities with natural forces, fostering a deeper understanding of yourself and the world throughout the year.