Abstract
It is already known that a BCK-algebra has the partially-ordered structure equipped with the least element, also it has a lattice structure when it is bounded and commutative, and when it satisfies the condition (S) and the commutativity. In this report, the authors create some concrete examples of BCK-algebras with different features on a representative simple lattice, and we investigate the characteristics of BCK-algebras from the viewpoint of the construction of lattice operations.