Japanese castle interior, Hishi Yagura, the diamond-shaped turret

The turret (yagura in Japanese) photographed here, Hishi Yagura of the Kanazawa castle, was built in a rhomboid or diamond shape (hishi in Japanese) with walls making angles of 80 and 100 degrees.

It is not known the reason behind this unusual design, but it is supposed to be related to the defensive role of the turret, because it was a watchtower of the second defense wall, and this shape probably allowed for simultaneous observation of two gates.