In list 2 of the 2nd tablet (lines II i 9-21), MUL.APIN contains the first calendar rule: It is written how to use Sirius and the observations of the moon in the 4th, 7th, 10th and 1st month to determine the cardinal points of the year.
The second tablet's list 2 (lines II i 9-21) contains the first calendar rule: It describes how to use Sirius and lunar observations in the 4th, 7th, 10th, and 1st month to determine the cardinal points of the year.