《汉书·志·律历志上》
五声在三正中，黄钟在子位为天正，林钟在未位，其相对冲的是丑位，为地正，太蔟在寅位为人正。
其于三正也，黄钟，子，为天正；林钟，未之冲丑，为地正；太族，寅，为人正。
The five sounds are in the three positives. The yellow bell is in the sub-position as the positive sky, the forest bell is in the wei position, its opposite is the ugly position, the positive earth, and the Taimu is in the Yin position as the positive person.