Because the pericardium meridian is at 19: 00 and the triple energizer meridian is at 2 1: 00, the pericardium meridian, triple energizer meridian, gallbladder meridian and liver meridian are in the same section, and their operation is influenced by the pericardium meridian and triple energizer meridian. This is why the ancients had the habit of resting at sunset.
-For reference.