Confining Nature to a Diagram: Origins and Evolution of the System of Seventy-Two hou 候

Abstract The seventy-two seasonal signs ( hou 候) divide the year into five-day intervals, each associated with a specific seasonal event. This system is out of step with observable nature, which calls for an explanation. A close analysis of early textual sources demonstrates that this system was designed as a way to extract meaning from natural phenomena for use in omenological interpretation, presenting cases when specified seasonal events failed to occur as meaningful portents. Misalignment with nature was therefore a desired element of the system of seventy-two hou , ensuring its capacity to consistently generate interpretable meanings. After the seventy-two hou were incorporated into the official calendrical system in the sixth century CE , their sequence continued to undergo major and minor revisions, based on shifting notions of the relative canonical authority of early texts.