[Project Summary] Karatsu has been a gateway to the continent since ancient times. During the Edo period, the Karatsu Domain was an important base for the Shogunate's governance of Kyushu, and was also a historical and cultural city where unique cultures such as Karatsu Kunchi and Karatsu ware flourished. What is expected of Karatsu Castle, the starting point of Karatsu tourism, is to utilize the charm of Karatsu's shining history and culture and play the role of a circulation device for walking around the city. We comprehensively reviewed displays, facilities, and operations, and aimed to redevelop it as a comprehensive facility and guidance facility for Karatsu City's "walking around the city" as a base to revitalize the region by maximizing the appeal of Karatsu Castle. We have consistently assisted with the basic plan, design, and construction. [Client's Issues] There were three issues with Karatsu Castle before the renovation. The first was that the client was eager to update the aging facilities, outdated displays, and outdated displays themes. The second was that Karatsu City's attractive resources were not being fully utilized, and collaboration with collections and other tourist spots was necessary. The third issue was safety and cultural property protection, and we needed to address issues such as natural lighting, universal concept design, earthquakes, and theft. By solving these three issues, we aimed to create a tourist base worthy of being a "tourism and cultural exchange city where authenticity shines, surrounded by nature, history, and culture." [Solution] In order to solve these issues, we aimed to realize an "displays that allows visitors to enjoy Karatsu," and actively utilized IT, such as developing displays story centered on the history of the castle town and the successive castle lords, creating an attractive displays space that makes use of Hizen domestic products illustrations and Karatsu ware, and introducing AR to explain displays. Next, we aimed to realize a "comfortable displays," creating a space with a sense of hospitality, such as a museum shop, reviewing the flow of people inside the building and taking into consideration those with weaker views, such as foreign tourists, installing toilets, stair lifts, and a multipurpose room. Furthermore, in order to realize a "safe displays," we enhanced the functions of the facility as an introduction to tourism in Karatsu, such as a tourist information corner, promoted mobility by disseminating information about tourist facilities, and thoroughly implemented risk management for accidents and losses. These are the three solutions we came up with. <Our project members> [Development] Yumeki Kusumoto [Sales and project management] Tatsuya Fujii and Yumeki Kusumoto [Planning] Takeshi Shin and Kyohei Kishida [design, layout] Masaaki Mitsunaga and Rie Morita [Production and construction] Takeshi Suezaki, Goro Yamano and Nanae Hori [maintenance management] Katsumi Yamada and Takatoshi Nakamura