Among the factors that determine facial shape, this refers to a method of refining the contour of the lower jaw bone, which defines the outline of the lower face, including the front chin area, in a sharper way.
A conventional square-jaw surgery typically refines the contour starting from below the earlobe to the corner area of the lips, but to make the face into a V-line, a procedure is needed to sharpen the front chin area and the surrounding areas more.
For this V-line facial contouring surgery, the appropriate surgical method should be selected according to the length of the front chin.
If the chin is short, the chin length must be extended (lengthened) so that the contour line leading to the surrounding area can connect into a sharp and smooth V-line. If the chin is long, the length should be appropriately reduced while the surrounding area is refined so that the heavy-looking impression of the front lower jaw can be corrected.
In addition, along with the procedure that refines the shape of the lower jaw bone described above, changing the conditions of the soft tissue may also help make the final facial shape into a V-line.

The above content is what the author presented at the "2008 Korean Society of Plastic and Reconstructive Surgeons Spring Meeting" and the "2008 Japanese Society of Aesthetic Plastic Surgery".