41 cm/45 3rd Year Type naval gun

The 41 cm/45 3rd Year Type naval gun is a 41-centimeter (16.1 in) breech-loading naval gun designed during World War I for the Imperial Japanese Navy. It served as the primary armament in the Nagato-class dreadnoughts completed after the end of the war and in coast defense mountings.

Source: Wikipedia — 41 cm/45 3rd Year Type naval gun (CC BY-SA 4.0)