Walls are built around castles and towers as protection. These walls are usually made of stone, and are mounted within the basic structure of the architecture.

Walled fortresses can be seen in many world civilizations. Although, the styles differ, the basics are the same; some are beautifully made and some have special features, such as ducts for discharging water.

In Japan, walling can be seen especially in castles and castle towns. The Ano Group from Kunie are famous for their designs of fortresses and their beautifully designed walls. Also, in the Ryukyu Islands, it was common practice to put stones on roofs and the surroundings to protect their houses from fierce winds and storms.

Ikuji-naka Bridge spans the Kurobe Fishing Harbor and is the first bridge in Japan that rotates to the side on a fixed axis. The current bridge is actually the 4th-generation version. The original was installed during the Taisho period, with the 2nd built during the early Showa period, and the 3rd during the 30s in the Showa period.

The 3rd generation was installed as an elevating bridge. Due to deterioration and the increase in size of fishing boats, the canal where the bridge was installed was expanded, and the third bridge was rebuilt as part of the general reconstruction.

The new fixed-axis bridge, which was completed in Showa 56, is what spans the canal today. The bridge is 38.4m long, 7m wide, and weighs 307 tons. The bridge can turn up to 78 degrees, and on a busy day, opens between 15 and 20 times.