[Project Overview] Karatsu has long been a gateway to the continent. During the Edo period, the Karatsu Domain was an important base for the shogunate's rule of Kyushu, and it was also a historical and cultural city where unique cultures such as the Karatsu Kunchi displays and Karatsu ware flourished. Our company believed that Karatsu Castle, the starting point for Karatsu tourism, should play a role in leveraging the charm of Karatsu's brilliant history and culture and acting as a circulating mechanism for walking tours of the city. Therefore, we comprehensively reviewed the exhibits, facilities, and operations, aiming to redevelop Karatsu Castle as a comprehensive guidance facility for "walking tours" in Karatsu City, a hub that will revitalize the region by maximizing the appeal of Karatsu Castle. Our company assisted with the basic planning, design, and construction from start to finish. [Client's Challenges] There were three challenges with Karatsu Castle before the renovation. First, the client desperately wanted to update the aging facilities, outdated displays, and outdated displays themes. Second, Karatsu City's attractive resources were not being fully utilized, and there was a need for collaboration with collections and other tourist spots. The third issue was safety and cultural property preservation, requiring measures to address issues such as natural light, universal concept design, earthquakes, and theft. By solving these three challenges, we aimed to create a tourist hub befitting a "city of tourism and cultural exchange where authenticity shines, surrounded by nature, history, and culture." [Solutions] To solve the challenges, we aimed to create displays that allows visitors to enjoy Karatsu, developing displays story centered on the history of the castle town and successive castle lords, realizing an attractive displays space utilizing the Hizen Province Products Illustrations and Karatsu ware, and actively utilizing IT, such as introducing AR displays explanations. Next, aiming to create a "comfortable displays," we created a welcoming space such as a museum shop, reviewed the flow of movement within the building and took into consideration visitors with disabilities, such as foreign tourists, and installed toilets, stairlifts, and a multipurpose room. Furthermore, aiming to create a "safe displays," we enhanced the functions of the facility as an introduction to tourist Karatsu, such as a tourist information corner, promoted the ability to move around by disseminating information on sightseeing facilities, and thoroughly implemented risk management for accidents and losses. In summary, we have put forward three solutions. <Our Project Members> [Development] Yumeki Kusumoto [Sales & Project Management] Tatsuya Fujii, Yumeki Kusumoto [Planning] Takeshi Kami, Kyohei Kishida [design, layout] Masaaki Mitsunaga, Rie Morita [Production & construction] Takeshi Suezaki, Goro Yamano, Nanae Hori [maintenance management] Katsumi Yamada, Takatoshi Nakamura