Three words within a traditional framework
Qi, yin and yang help traditional authors describe life, relationships and change. They are not three nutrients or ingredients. PolyU’s introduction describes qi as a foundational traditional concept associated with movement and life activity, and presents yin and yang as relational categories.
Keep the original word qi when reading English. Translating it as “energy” can be a loose aid, but it can also imply a measurable physical quantity that the passage has not established. Calories, electricity and oxygen each have specific meanings; none is an automatic substitute for qi.
Yin and yang always invite a comparison
The original shaded and sun-facing slopes provide a useful starting image. The point is a relationship, not that one slope contains a substance called yin. In traditional analogies, darkness and stillness are associated with yin, brightness and activity with yang. Neither side is a moral judgment.
CUHK’s explanation uses the seasons to show how context changes the comparison. Spring and summer are grouped on the warmer, yang side relative to autumn and winter; within the first pair, spring is relatively yin and summer relatively yang. Before assigning a label, ask “relative to what, and in which respect?”
Balance is not a recipe for equal amounts
CUHK explains traditional harmony as a relationship through changing conditions rather than simple numerical equality. This matters when popular writing turns “balance” into a rule to eat equal amounts of two food categories. The concept does not supply such a calculation.
As an editorial analogy, think about the changing pattern of day and night across a year. The analogy illustrates change and relationship; it does not diagnose the body or prove a mechanism. A yin–yang diagram cannot tell you how many grams of an ingredient to add to dinner.
Read qi in the sentence, not in isolation
In food writing you may meet “nourish qi,” while other texts discuss qi movement or use compound terms. Start by asking what the author is describing: a traditional action attributed to a material, an account of bodily function, or a practitioner’s assessment. The same short word does not make all these statements interchangeable.
For example, “this food traditionally nourishes qi” tells you how the source categorizes it. To claim the food improves endurance would require separate evidence measuring that outcome with the relevant food. The second statement does not follow from translating the first.
Do not collapse different traditional terms
A traditional qi concept is not identical to yin or yang. Nor is the phrase “four qi” on a materia-medica page a list of four measured energies: PolyU explains it there as the cold, hot, warm and cool properties. Context and compound words change what a term is doing.
This is why a glossary should lead you back to the full passage. Record the original characters, the material or person being described and the source’s explanation. A one-word English translation often leaves out the relationship that made the sentence meaningful.
From understanding words to choosing a next step
Labels such as yin deficiency belong to traditional assessment, not to the nutrition information on a package. CMRO describes assessment as bringing together several methods and a person’s history. Finding one matching description online does not complete that process.
For a practical reading exercise, open one ingredient page and separate its everyday identity, its traditional description and any modern evidence. Then read the warming-and-cooling guide. You can understand these distinctions without assigning yourself a constitution or choosing a remedy.