Triangle is a boat-access artificial reef off Manazuru with a compact profile, plenty of fish, and an easygoing feel that works for new divers as well as photographers. The steel-frame structure gives the site both macro and wide-angle appeal, with schools of fish in summer, nudibranchs in winter, and enough reef texture to make repeat dives interesting. It is one of the more approachable boat sites in the Iwa area, especially with local guidance from the Manazuru diving centers.