The Hamaguri Gomon Gate is one of the nine outer gates of the Kyoto Imperial Palace. Its original formal name was "Shinzaike Gomon Gate." This gate is a Kōrai-style gate reinforced with metal bars. It was rarely opened, but during a fire at the Kyoto Imperial Palace, the gate was forced open by the heat, leading to its nickname "Hamaguri Gate," like a clam that opens its mouth when heated. The gate is also famous for the fierce battle that took place there during the late Edo period, known as the Kinmon Incident, where Choshu forces clashed with Aizu and Kuwana forces. Even today, bullet marks from that time remain on the gateposts.