“Korokan” is one of the ancient guest houses for foreign diplomacy built in Heian period (794-1185). The guest houses were set up in three locations; Heiankyo (Kyoto), Namba (Osaka) and Chikushi (Fukuoka). Among them, “Korokan” of Chikushi is the only one whose original location has been indentified here in Chuo-ku, Fukuoka. The house was mentioned in an ancient book of 688 as “Tsukushi-no-Muromitsu”, and in Heian era, they changed the name in Chinese-style as “Korokan”. It is said that the house had ushered the imperial embassies and missions from China (Shilla) for about 400 years from the end of 7th century to 11th. The remains were first discovered in 1987 prior to the renovation of the outfield seats of Heiwadai baseball stadium, and in the following year started the excavation research. The museum exhibits remains of the building and ancient trading articles. There is also a display on the history of diplomacy.