This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
Needham's documented history of Chinese mathematical astronomy traces how the five phase seasonal scheme, tying spring to wood and the east, summer to fire and the south, autumn to metal and the west, winter to water and the north, with late summer as a fifth transitional phase tied to earth and the center, developed as part of a broader, internally consistent correlative cosmology rather than as an isolated calendar convention, and records the specific solar terms, Lichun among them, that traditionally mark a season's documented start within the Chinese calendar.
That documented history is useful for comparison precisely because it developed independently of the Western tropical quarter system Ptolemy's astrology assumes, and Needham's account lets an entry state honestly where the two traditions' seasonal reckonings substantially agree, both track the sun's real annual path even though they name and divide it differently, and where a fifth season with no four quarter equivalent shows the two systems are not simply the same division wearing different labels.
An entry draws on this documented comparative history to keep each tradition's own seasonal logic intact rather than collapsing a five phase and a four quarter scheme into a single description neither tradition would recognize as its own.