The type 93 (1) or “Long Lance” used by surface units (and only surface units) of the Imperial Japanese Navy was the most effective torpedo of World War Two hands down. So nicknamed for its range and not its length, the “Long Lance” type 93 (1) had a warhead weighing 1,080 pounds (490 kilograms) and had a maximum range of 43,700 yards (39,960 meters) at its lowest speed setting of thirty-six knots. (Type 93 (3) became available in 1943. The warhead weighed 1,720 pounds (780 kilograms) and had a maximum range of 32,800 yards (meters 29992) at thirty-six knots.
Japanese submarines used a smaller, albeit just as effective torpedo, known as the Type 95. However, this type did not carry the nickname “Long Lance.” This is sort of confusing and confused me for a long, long time until I researched the damn thing for a number of hours.
[Sources: Naval Weapons of World War II by John Campbell and The U.S. Navy Against the Axis: Surface Combat, 1941-1945 by Vincent P. O’Hara. Image courtesy of Wikipedia.]