The Nagoya Castle Ruins are about a 30-minute taxi ride from Karatsu Station. Alternatively, from Karatsu Oteguchi Bus Center take a Showa Bus on the Yobuko Line to Nagoya-jo Hakubutsukan Iriguchi stop (translates to “Nagoya Castle Museum entrance”) (35–55 minutes). Then, walk about five minutes to the castle ruins. Please note that some bus routes are direct, while others require transfers.