. This explains why the recorded solar eclipses in the early Han dynasty often occurred one day (and sometimes two days) before the calendrical conjunction days. The lunar cycle in the <i>s&#236;f&#275;n</i> system is slightly longer than the synodic month. The conjunction times would be one day later, on average, after about 300 years. This is why it's obvious from the figure below that the time lags of the calendrical conjunctions appear to increase steadily.</p>
    
<figure>
<img src="QinHanConjTimeLag.