The purpose of this paper is to clarify the actual situation of land reclamation caused by the local landlord in Medieval Japan, focusing on the relationship between his residence and the evolution of irrigation systems. This paper lends weight to studies of village landscapes in Medieval Japan, consisting of settlement, landlord's residence, irrigation canals and paddy fields. It seems reasonable to suppose that the social structure of the seigneurial regime is reflected in the spatial structure of Medieval landscapes.
Considering irrigation systems from a spatial point of view, the author demonstrates that the location of the landlord's residence is closely related to the structure of paddy field irrigation in the Medieval Period. It followed that the local landlord constructed irrigation systems, and reclaimed waste land such as terrace surfaces and alluvial fans. Particularly in the early Medieval Period, the local landlord was concerned with the formation of the manorial system, being in complete control of Kannou-with rights being mainly based on water supply.
The case study of the Ane River basin made it clear that the local landlord-Kokujin-Ryoushu-strengthened his control over irrigation in the 14th century. It has been generally considered that the developing village community, So-son, was responsible for the construction of irrigation systems and the reorganization of villages in the latter Middle Ages. However, the author demonstrates that the role of the local landlord in such situations was much more important than had been expected since it is obvious that some nucleated settlements were formed under his leadership. The spatial structure of such nucleated settlements reflects the process of Kokujin-Ryoushu expanding his territory by making his branch families invade the villages.
The author considers that the purpose of studying landscape is not only to restore the different components of landscape to their original state, but also to clarify the driving forces behind its formation. Therefore, in future, it will be more important to emphasize the formation process of landscape in any historical geographical inquiry.