Taijitu is still. In stillness it generates "yin"; yet at the limit of stillness it is also active. Activity and stillness alternate; each is the basis of the other. In distinguishing "yin" and "yang", the Two Modes are thereby established. The alternation and combination of "yang" and "yin" generate water, fire, wood, metal, and earth. With these five [phases of] "qi" harmoniously arranged, the Four Seasons proceed through them. The Five Phases are simply "yin" and "yang"; "yin" and "yang" are simply the Supreme Polarity; the Supreme Polarity is fundamentally Non-polar. [Yet] in the generation of the Five Phases, each one
Yin and yang "to shelter; shade", and 陽 or 阳 "sunny" is always pronounced with rising second tone "yáng". Sinologists and historical linguists have reconstructed Middle Chinese pronunciations from data in the (7th century CE) "Qieyun" rhyme dictionary and later rhyme tables, which was subsequently used to reconstruct Old Chinese phonology from rhymes in the (11th-7th centuries BCE) "Shijing" and phonological components of Chinese characters. Reconstructions of Old Chinese have illuminated the etymology of modern Chinese words. Compare these Middle Chinese and Old Chinese (with asterisk) reconstructions of "yīn" 陰 and "yáng" 陽: Schuessler gives probable Sino-Tibetan etymologies for both Chinese words. "Yin"