The 14 cm/40 11th Year Type naval gun was the standard surface battery for Japanese submarine cruisers of World War II. Most carried single guns, but Junsen type submarines carried two. Japanese submarines I-7 and I-8 carried an unusual twin mounting capable of elevating to 40° . Eleventh year type refers to the horizontal sliding breech block on these guns. Breech block design began in 1922 AD, the eleventh year of the Taishō period. The gun fired a projectile 14 centimeters (5.5 in) in diameter, and the barrel was 40 calibers long (barrel length is 14 cm x 40 = 560 centimeters or 220 inches).