Because there is a small amount of float 0.4 cm in the front pverse collar of the base type, only when the width of the pverse opening is increased, can the front horizontal open collar loose and flat, and the leading line of the shoulder seam can not be placed in front of the collar. Therefore, the difference between the front and the back collar width can be increased to 0.4 to 0.5 centimeters. After the straight open collar is deep, 0.2 centimeters should be shrunk, which is 2 to 2.3 centimeters, so that the front arc can be avoided.