Four principles of pluggable habitation.

Every unit is a machine part.

A capsule is stamped, welded, and bolted like an appliance chassis — swapped on a 25-year cycle, never repaired in place.

Steel truss · 4 bolts · 2.5 tonnes

The core outlives the shell.

Two reinforced-concrete service towers carry water, waste, and stairs. Capsules plug on and off without touching the spine.

Two cores · 140 sockets · load-bearing

Weathering is honest.

Galvanized rib panels dull from silver to a pale grey. The building is meant to look like it has been outside — never clean, never white.

Kenitex spray · rib-reinforced steel

One porthole, one interior.

A single 1.30 m circular window per capsule. Behind it: bed, radio, desk, bath — a compact instrument for one Ginza salaryman.

2.30 × 3.80 × 2.10 m · 10 m²