The Kahoku-mon gate, which is the "front face of the San-no Maru (the third enclosure)" and virtually the main gate of Kanazawa Castle, is located on the top of Kahoku-zaka Hill past the front castle gate. The Kahoku-mon gate is referred to as one of the three major gates of Kanazawa Castle, along with the Ishikawa-mon gate (listed as an important cultural asset of Japan) and the Hashizume-mon gate. After a major fire in 1759 consumed most of the Kanazawa Castle buildings, the Kahoku-mon gate was reconstructed in 1772.
After the reconstruction, the Kahoku-mon gate served as the main gate of Kanazawa Castle for practical purposes until it was demolished around 1880. After an interval of 130 years, the Kahoku-mon gate returned to life. The construction work took about two years and a half, starting in November 2007 and reaching completion in April 2010.
Based on available drawings, old photographs and documents, as well as findings from archaeological research, the restoration work respected the historical facts and used time-honored Japanese construction methods. Here the skills of the artisans and carpenters of Ishikawa are demonstrated to the full − in the detail of the structure and finishing, such as the stone walls made with Tomuro stone, the white walls finished with plaster, the framework carpentry, and the lead-tile roofing.
Gojouchuu-ichibu-goezu, a map of Kanazawa Castle created in 1830, and old photographs taken during the Meiji period were important materials for the restoration of the Kahoku-mon gate.
The restoration also made use of the foundation stone and other buried assets excavated during the archaeological research.
The side facing the Masugata (the rectangular space between the first and second gates), which contains an oriel window for dropping stones on enemies, forms the front of the Ni-no Mon. Three-millimeter-thick steel plates are tacked on the doors, pillars and beams, along with other defensive accessories. The second floor serves as a watchtower. Its interior walls and flooring are made of Noto hinoki cypress lumber, like those of the Ishikawa-mon gate.
The Ichi-no Mon is the first gate for entering the San-no-maru (third enclosure). This gate, 4.7 meters wide and 7.4 meters tall, is built exclusively of zelkova lumber. The side earthen walls, covered with square tiles jointed with plaster (so called “Namako Kabe” or sea cucumber walls), have concealed crenels. During battle, the covering of the walls at the crenels is broken so that guns may be pointed through them.
The Kahoku-mon gate had had a two-story watchtower, as with the Ishikawa-mon gate, before it was burnt down by the great fire in the Horeki period. However, the reconstruction in 1772 provided the watchtower with earthen walls and an oriel window. The latest restoration follows this latter model.