The issue of carrier space and the spatial characteristics of Edo middle-lower samurai residences from a space syntax perspective: reinterpreting spatial evolution in modern Japanese urban housing

This study analyzes the spatial configuration of Edo middle-lower class samurai residences using space syntax theory, focusing on the relationship between internal and external spaces. To address limitations in conventional modeling, three segmentation approaches for external space are compared: exclusion, single carrier space, and multiple segmented spaces. Based on this, a Modified Carrier Space model is proposed to better represent the extroverted spatial structure of these residences. Using this model, 77 housing cases were analyzed. Results show that external spaces such as entry courts, family yards, and gardens constitute approximately 35% of all convex spaces and play a central role in spatial hierarchy and circulation. Transitional spaces like the Engawa, Genkan, and Doma enhance interior and exterior integration. The model shows balanced integration across spatial layers, supported by a Base Difference Factor of 0.819 and 12 ring structures. These findings suggest a consistent spatial pattern and the presence of hereditary typologies. The openness observed also challenges conventional interpretations based on Sekkyaku-honi. This study introduces a new analytical perspective that deepens the understanding of spatial meaning in traditional Japanese housing.