When you start to use the compass, you must recite this formula.

Compass entries must recite the formula:

Between virtual danger and danger, the needle is clear, and Zhang Su is prosperous. The ridge is far from the correct position, but this difference is invalid.

Set the warp on the hill first, but compare with the middle needle. The middle needle is 27 and 38 more. Don't talk to the teacher. Explanation:

The formula of compass is to set the dial of heaven and earth first, with the needle ring in the north and the needle point in the south. First, aim the crosshairs at the longitude of the dial with a compass. Both of them are full-time, leaving three degrees in the south, which is dangerous in the north. Then move the dial to designate the needle point in the south as Wushan Mountain and align it with the red line of the chassis. The three lines are in the same position and aligned correctly, so as to determine whether the compass is correct.

The user must use the south needle to specify the meridian, with the north noon south as the front plate and the needle tip pointing to the back plate. Later generations are self-taught, and it is idle not to know the inside story. The number of layers of the compass is wonderful, and the compass used must be carefully taught by Master before it can be used freely. No matter what tomb it is, the south needle should be carefully parallel to the bottom red, which is the name of the compass.