The Kagerou-class destroyers (陽炎型駆逐艦), also called the Destroyers Type-A (甲型駆逐艦) from their plan name. In 1937, Japan withdrew from the London Naval Treaty and the Kagerō were designed free from these restrictions, utilizing experience drawn from previous classes.
Preceded by the Asashio-class, this classically Japanese design combined speed, range, firepower and stability in equal and eminently successful proportions. When introduced, they were among the deadliest destroyers afloat, primarily due to the excellent range and destructive force of their 'Long Lance' torpedos. However, the lack of radar equipment hindered their otherwise superb design and, as with most pre-World War II ships, the Kagerou-class were also deficient in anti-submarine and anti-aircraft weaponry. However this was remedied over the course of the war by adding more depth charges, AA weaponry, and later radar equipment.
By the beginning of the Pacific War the Kagerou-class formed the backbone of the Empire's first-line destroyer strength, comprising the 4th, 15th, 16th, 17th, and half of the 18th Destroyer Divisions.