宗四分比丘隨門要略行儀 1.37

1.37

The third contemplation is knowing the time and count of receiving the precepts. [One should say,] 'I, in such-and-such a year, month, day, and time, received the complete precepts; [at that time, the shadow of] a one-foot stick was such-and-such a shadow.' (If one has no varṣā [rains retreats]; if one has varṣā, one declares it according to the amount).