The so-called phonetic loan characters in transmitted early texts and what are generally called ‘phonologically related textual variants’ in excavated late Warring States to early Western Han manuscripts can both be accounted for by systematic structural variability of character forms in the early Chinese writing system. In the process of inventing a compound character for a given word, alternative choices were available from sets of graphs that denote meanings of the same semantic category and from ones that stand for words with the same syllabic value for use as components in any new character. These non-unique selections of graphic components for one and the same word are reflected in the writing system of the Zhou period respectively as systematic alternations of signific and phonophoric elements of the same functional value, viz., Synonymous Significs (SS) and Equivalent Phonophorics (EP). The fact that refined Western Zhou ritual bronze inscription texts circulated across regions together with the apparent overall agreement on the use of phonetic components between the Qin and Chu scripts in all likelihood testifies to the existence of an elaborate orthographic meta-system, as opposed to the writing system itself at any given time or any individual region, well before the Warring States period. In reading a Chu manuscript in comparison with its transmitted counterpart or examining it for the study of historical phonology, we ought to consider the probability of SS and EP originating from an early period as a part of the historical meta-system.