The Principal Tower of Nagoya Castle was repaired on a large scale from 1752 to 1755. This paper evaluates and analyzes the Principal Tower based on historical drawings and specifications, which explain the repair of the main body of castle tower. The northern and the western parts of the first and the second layers on the top of the stone wall of the Principal Tower were dismantled before the stone wall was dismantled. Also, the builders cleverly applied a system of levers. Then the subsidence and the inclination of the Principal Tower were fixed logically and systematically using the system.
