Firstly, this is achieved by adding backgrounds such as clouds, waves, and flowers. Which has the effect of making the main theme stand out. It is in the same way as framing a painting.
The Literal translation of Gaku 額 is “framed”, Bori 彫り is “tattoo”. Gakubori has specific shapes and formula.

Only the arms and back piece are possible to arrange independently with Gakubori.
The abdomen and legs are assumed to be connected to them. They alone by themselves can not be completed as Gakubori in any case.
Consequently, the legs added together with the abdomen after the arms and back are finished.

• Gaku of the arm must be from the chest(Hikae). However, there is several type of the shape of Hikae. So you can choose it small one to large one.
• Stopping just above the elbow called Go-bu(half sleeve tattoo), below the elbow called Shichi-bu or Hati-bu(quarter sleeve tattoo). And all the way up to the wrist called Nagasode(full sleeve tattoo).

• The form of Gaku on the back is from a little above the back of the knee to just under the neckline called Kameno-kou or Sewari(full back piece tattoo).

• The form of front Gaku consists of two types. One which features a gap of untattooed skin roughly one fists width positioned vertically in the middle called Munewari. And a type that fills the whole area called Donburi.

• The leg forms of Gaku in the case of Munewari can be straight down on thigh and drawn in an arc to connect with the bottom of Sewari. Also, it can be tattooed up to just above the knees (Han-zubon), tattooed to under the knee (Shichi-bu or Hachi-bu), or tattooed to just above the ankle (Naga-zubon).

• In case of Donburi, it can be only Han-zubon, Hachi-bu or Naga-zubon.

• It can only be called Sousin-bori(full body suit tattoo) after filling the entire body. In addition, with the exception of the hands, feet, head, neck and also genital area. These areas are extra option.

These shapes of Gaku and names vary slightly depending on the tattoo family(Ichimon) or region.