《晋书·志·第六章》
以六十律对应期，黄钟从冬至这天开始应验使用，到下一个冬至日复还，其间阴阳、冷热、风雨的占验就产生了。
以六十律分期之日，黄钟自冬至始，及冬至而复，阴阳、寒燠、风雨之占生焉。
The sixty pitches correspond to the seasons. Huangzhong starts from the winter solstice and ends at the next winter solstice. In between, it will indicate the changes of Yin and Yang, the changes from cold to warm, win, and rain.