The Type 10 or 12 cm/45 10th Year Type naval gun was a Japanese 120 mm calibre dual purpose anti-aircraft and coastal defense gun used during the Second World War.

[2] The weapon was originally designed for ship use and was produced in large numbers during 1944.

To compensate for muzzle preponderance, spring equilibrators are mounted below the gun barrel.

A semi-automatic horizontal sliding-wedge breech is used and Fixed QF 120 x 708R ammunition was used.

The gun fired either high explosive or incendiary shrapnel shells that weighed 20.6 kg (45 lb 7 oz), with a complete round weighing 32.4 kg (71 lb 7 oz).