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°. The appended designation 11th year type refers to the horizontal sliding breech block on these guns. Breech block design began in 1922, or the eleventh year of the Taishō period in the Japanese calendar.Campbell 1985 pp.173 & 191 The gun fired a projectile in diameter, and the barrel was 40 calibers long (barrel length is 14 cm x 40 = 560 centimeters or 220 inches).Fairfield 1921 p.156
