The Lean Startup shows that Minimum Viable Product (MVP) can create new business. However, it doesn’t show how to actually make MVP. This study shows a structured service design model based on the perspective of external and internal constraints. By utilizing the vertical and horizontal approaches, we can find out multiple viewpoints which are required to perform system design. The models show a thinking process in which external and internal constrains are alternately adjusted and a MVP that satisfies all constraints is finally identified. These are able to explain pivot based inheritance of MVP.