Nagoya Castle - Keeps

Keeps

Nagoya Castle is known for its unique "connected-donjon" style of construction, with the main donjon of five stories on five different levels and a smaller donjon of two levels joined by an abutment bridge. Evidence that another small donjon was planned for the west side of the main donjon can be found in traces of an entryway in the upper part of the stone wall foundation on that side. The entryway to the small donjon was also planned for the west side. However, during the construction, the location was changed to where it is today. Traces of the original entryway remain inside the stone wall.

Various types of weapons were stored on the first level of the castle's main donjon. Flammable materials such as gunpowder were kept in facilities outside the castle.

The small and main donjon both burned down during World War II and were reconstructed in 1959.

The job of constructing the castle walls was divided among twenty feudal lords, including Kiyomasa Kato. The walls of the donjon were built by the Kiyomasa family and the cornerstones of the building bear the inscriptions of the family members in charge of the construction. Those of Kato and his retainers can be seen on the northeast corner. In the stone walls of the castle, there are marks of figures of triangles in circles, and the rough outlines of folding fans, war fans, and other objects. These are called kokumon (carved crests), and represent the different daimyo lords and their vassals who were apportioned sections in the construction. The signs were carved into the stone so that there would be no mistake as to which lord contributed which stone in the transportation, and to avoid disputes. Some of the foundation stones of the main castle tower were moved to a lawn on the north side during the 1959 reconstruction, due to damage from the immense heat of the fire and subsequent collapse of the tower.

The stone wall supporting the donjon was constructed by the technique called ogi kobai or "fan sloping", by which the upper part of the wall is curved outward like a fan. This wall is also called the Kiyomasa-style Crescent Stone Wall, after the general and engineer Kiyomasa Kato, who was in charge of its construction. The fan sloping technique was used to prevent swelling by curving the middle portion of the wall inward, thereby evenly balancing the stone weight against the pressure of sand and earth within.

There is a roofless corridor between the main and the small donjon. The walls in this corridor were earthen and stone. Mounted on the outer part of the west side are numerous 30 centimetre-long spearheads to thwart enemy climbers from coming over the eaves. A similar sword-fence can be found at the Fumei Gate, facing the east side of the main donjon.