This pass was used by the king’s guards when they passed through the main gate of the city at night. The pass was divided in two sections. One piece was left in the night duty room of each gate and the other piece was submitted to the guard on duty. On each pass, the relevant gate and time zone were written. Several different kinds of passes were used for five time-zones of each gate: Heunginmun (East Gate), Donuimun (West Gate), Sungnyemun (South Gate), and Hyehwamun (Northeast Gate). The five time-zones consisted two hours each from seven o’clock in the evening to five o’clock in the morning.