Three related but independent propositions are put forward and investigated: (1) a revised version of a theory of the Old Chinese rhymes based on the assumption that there were only two rhyme vowels, ∕ə∕ and ∕a∕, and eighteen final consonants, namely, labials -p, -m, dentals -t, -n, -l, -s, velars -k, -ŋ, -ɤ, palatals, -kj, -ŋj, -j, labiovelars -kw, -ŋw, -w, and palatolabiovelars -kɥ, -ŋɥ, -ɥ (as found in the modern Fuzhou dialect); (2) a revised version of a theory that the ten Heavenly Stems and twelve Earthly Branches originated as phonograms naming acrophonically the initial consonants of the Chinese language at the time of their invention, the consonants being the same as those reconstructed finally, with the addition of the fricatives x-, xj-, xw-, xɥ-;(3) a hypothesis to explain the calendrical use of these signs on the assumption that the Stems were chosen, as far as possible, from signs with the same initial consonants as the numerals from one to ten, while the remaining twelve signs were treated as a supplementary series of twelve.