The top of the Luban ruler is the door meter, and the bottom is the Dinglan ruler. The door meter is used for the construction of Yangzhai, and is used for the measurement of house construction and household appliances for living people, while the Dinglan ruler is used to measure the yin house and ancestor tablets. The red marked on the ruler is auspicious, and the black is unlucky. Just find the meaning of the words marked on it according to the size of the things measured.

Precautions for using the door meter:

1. Generally, when measuring things, you should choose the auspicious red letter.

2. Wealth belongs to you and should be measured carefully.

3. The red letters between financial capitals are all auspicious.

4. Yimen is used for religious education in temples, Taoist temples, schools and other places. Do not use the word "yi" indiscriminately on residential doors to avoid disaster.

5. God’s thrones and Buddhist utensils are also measured using the door meter, and the word “cai” or “ben” should be used.

6. Generally speaking, it would be best if the yin and yang can be used to benefit both yin and yang, but in general it is best to take the red letter between wealth and capital.