There are many culturally and historically important gate constructions at Nijo (二条) caslte. Among them, Homaru Yaguramon* (本丸櫓門) gate, a national important cultural property of Japan, is the most valuable one since it's the only survivor of big fires occurred many times in Kyoto. *Yugura means turrets at castles in Japanese.
Even in the Edo (江戸) period, a era of peace, people never forget to prepare for wars. The wooden bridge in front of the gate was able to be dropped into the water so as to prevent invasions, and the gate itself is inflammable since it is wrapped with copper plate.
The castle is very beautiful, yet still have many charms other than the beauty.