"We now understood how the front display matched the description in the back-cover user’s manual, with the sun and planets shown by marker beads on concentric rings. The front cover also displayed the moon’s phase, position and age (the number of days from a new moon), and the dragon hand that showed eclipse years and seasons.
With the concentric rings for the planets, we realized that we could now make sense of the front-cover inscription as well. This writing is a formulaic list of the synodic events of each planet (such as its conjunctions with the sun and its stationary points) and the intervals in days between them. On the back plate, the eclipse inscriptions are indexed to markings on the saros dial. On the front plate, inscriptions about the risings and settings of stars are indexed to the zodiac dial. Our insight was that the inscriptions on the front could refer to index letters on the planetary rings: if the sun pointer is at one of these letters, then the corresponding inscription entry describes the number of days to the next synodic event."