Oten-mon Gate (応天門)

It is written as 応天門 or 應天門. A gate that was placed in the palace district of Luoyang, the capital in the Sui and the Tang eras (China).

A gate placed in the palace of Heijo-kyo Capital and a gate placed in the palace of Heian-kyo Capital (Japan).
Details are described as follows:

A gate placed at Heian-jingu Shrine

An Oten-mon Gate (応天門 or 應天門.) was located on the back side of the palace of the Heijo-kyo Capital and another Oten-mon Gate on the back side of the palace of the Heian-kyo Capital: The Oten-mon Gate constituted the official gate to Chodoin (Hasshoin) where government operations and important ceremonies in the Imperial Court were executed. Located immediately north of Suzaku-mon Gate, it was an important gate together with the Suzaku-mon Gate and Kaisho-mon Gate.

When Japan introduced the Ritsuryo system (a system of centralized government based on the ritsuryo code) used in Sui and Tang in China, Japan built its capital and castle under a strong influence of the designs of the capitals and castles in Sui and Tang. It is said that the characters on the long horizontal board on the Oten-mon Gate in Heian-kyo Capital was written by Kukai, a famous priest. It is well known that the gate was set fire in Otenmon Incident in 866, but the gate was also lost many times and had never been reconstructed after it was destroyed in a conflagration in 1177. The Oten-mon Gate in Heian-jingu Shrine is a 5/8-sized imitation of the one in Heijo-kyo Capital.