Gatsu are artifacts which contain different hidden powers in each of them. The overall power of the Gatsu are not arranged by the month arrangement. The Gatsu are black in color that take shape in a medal form. Gatsu are given to the members of Jūnigatsu by its leader, randomly. In order to harness its power, first the artifact must be held by a person for some time until it acknowledge the person as master; it can be done by wearing it. A master will gain access to its secret power. There are twelve Gatsu named on the real months and an extra Gatsu known as "Jūsangatsu", the Thirteenth Month.