十二辰是天文学上的名词,辰也称“支”或“子”。原来成国最早的纪日方法,并不是以太阳和月亮作为依据,而是采用了‘干支六十周期”的体系,即以子、丑、寅、卯、辰、巳、午、未、申、酉、戍、亥十二个字作为一组,称为“十二子”;以甲、乙、丙、丁、戊、己、庚、辛、壬、癸十个字作为另一组,称为“十干”;干、支相互组合,就成了六十组由两个单字组成的作为周期符号使用的“序数”,以此周而复始不断循环。这些字早在殷商时代的甲骨卜辞中已经出现,可算得是源远流长的了。至于用它们来纪年,时间还要晚些,大约在西汉末年才开始。此后“十二子”也用于计月、计 Twelve stars are astronomical terms, and Chen is also called “branch” or “son.” The earliest method of dating to Japan was not based on the sun and the moon. Instead, it adopted the system of ’sixty cycles of dry support’. That is, the son, ugly, monk, dragonfly, chen, neon, noon, no, shin. The word “Twelve Sons” is used as a group of twelve characters, which are called A, B, C, D, E, J, G, S, 壬, and 癸. “Ten Dry,” and the combination of stem and branch, has become the “ordinal number” of the sixty-five group consisting of two single-word symbols used as periodic symbols, which are continuously recurring around the clock. These words were already in the Oracle inscriptions of the Shang Dynasty era. Appearing, it can be regarded as a long history. As for the use of them to mark the age, the time will be later, about the beginning of the Western Han Dynasty. After that “Twelve children” is also used for counting months, counting