The Kongō-class Battlecruiser (金剛型巡洋戦艦) were built before WW1. Designed by British naval architect George Thurston, the lead ship of the class was the last Japanese capital ship constructed outside Japan, by Vickers. The design of the Kongō-class battlecruisers came about as a result of the IJN's modernization programs, as well as the perceived need to compete with the British Royal Navy.
Following Japan's withdrawal from the London Naval Treaty, all four underwent a massive second reconstruction in the late 1930s. Following the completion of these modifications, which increased top speeds to over 30 knots (56 km/h; 35 mph), all four were reclassified as fast battleships.
They were the most active capital ships of the Japanese Navy during World War II, participating in most major engagements of the war. Hiei and Kirishima acted as escorts during the attack on Pearl Harbor, while Kongō and Haruna supported the invasion of Singapore. All four participated in the battles of Midway and Guadalcanal.