This renovation project addresses a timeworn two-family house tucked away in a narrow alley in Kamakura. The site, accessed only by a 1.3-meter-wide path, made reconstruction unfeasible and necessitated an approach based on the existing structure. The design is guided by two operative concepts: mitate, a reinterpretation of spatial meaning, and kasane, the physical layering of new elements over old. Rather than erasing, the project embraces accumulation—adding structural and temporal thickness through layered interventions. The resulting architecture gains strength not through replacement, but through continuity.