Hakozakigu (筥崎宮) is the most prestigious shrine in Chikuzen Province (筑前国) and considered to be one of the three great Hachimangu in Japan. The other two involve Iwashimizu Hachimangu (岩清水八幡宮) in Kyoto and Usa Jingu (宇佐神宮) in Usa city, Ohita Prefecture. Hako (筥) means oval-shaped box.
Since the shrine is named Hachimangu, the enshrined deities are 15th Emperor Ohjin (応神天皇), his mom Empress Jingu (神功皇后), and Tamayorohime (玉依姫).
The shrine started it's history in AD 921 when the spirits of above enshrined deities were transferred from Daibu Hachimangu (大分八幡宮) located in Fukuoka Prefecture. Initially Hakozakigu was located by the Genkai sea (玄界灘). Two years later (AD 923) it was moved to the current location.
The shrine is famous for its plaque "敵国降伏" denoting "Surrender of the hostile nation". The plaque was the enlarged version of its original one written in plain paper by the 60th Emperor Daigo (醍醐天皇) in AD 922. He prepared 37 copies because the main hall was composed of 34 pillars and three deities were enshrined (altogether 37). Besides he was 37 years old when he wrote. It became well-known when Emperor Kameyama (亀山天皇) wrote it in AD 1274 because Mongol invasion (元寇) took place then.
As you can see, it was raining like crazy when I was there:(((