Updated: May 28, 2020
An excellent main door must have a generous size and uses the measurement of the Lu Ban ruler. The door is the mouth of the house. It has to accurate to obtain the balance of the yin and yang. Lu Ban ruler used in constructing the main house door. It indicates at every inch a reading of the following:
財 Wealth: Invite wealth.
病 Sickness: Invites supernatural which may cause harm.
離 Separation: Cause quarrels.
義 Connection: Auspicious door that may bring harm which test bonds such as piety.
官 Official: Good to use for offices which invites glory.
劫 Robbery: Gives nuisance and troubles.
害 Harm: Causes harm to the dwellers from accidents, cheating and so on.
吉 Auspicious: Brings good energy and wisdom.
Background of Lu Ban 魯班
Lu Ban (c. 507–444 BC) was a Chinese structural engineer, inventor, and carpenter during the Zhou Dynasty. He is revered as the Chinese god (patron) of builders and contractors.
Lu Ban was born in the state of Lu; a few sources claim he was born far to the west, in Dunhuang, to a family of carpenters or artisans during the Spring and Autumn period of the Zhou dynasty. His original name was Gongshu Yizhi. He was also referred to as Gongshu Ban or Pan. He was supposed to have been an indifferent pupil until the scholar Zi Xia kindled his love of learning. He later learned woodworking from Bao Laodong. The enormous demand for his work supposedly compelled him to invent or improve several carpenter's tools—the saw, the square, the planer, the drill, the shovel, and an ink marking device—to complete his many projects more quickly. His wife was also credited with inventing the umbrella to permit him to work in inclement weather