Armor-piercing and armor-hiding is a concept in numerology, which means that there are one or more heavenly stems hidden in each earthly branch, and the heavenly stems are the same as those in earthly branches. In numerology, the significance of thorough heavenly stem lies in being able to better show and develop the character, ability and fortune of the task owner. There are three days in the Jiayin column that are hidden in the ground branch, and the armor is exposed, so it is called wearing armor.
Solemnly declare: the above contents are for reference only, please don't be blindly superstitious.