The Tone-class cruiser warship group of the Imperial Japanese Navy (IJN) of World War 2 (1939-1945) numbered just two ships - IJN Tone and IJN Chikuma. The class represented a heavy cruiser design that sought to combine the powerful armament of the earlier Mogami-class cruisers within a lighter 8,500 ton displacement range. This was done in an effort to produce a more powerful warship within the naval treaty limitations of the period.
The end-result was, instead, a class displacing 11,215 tons under standard load but powerfully-armed through a main battery of 8 x 203mm guns in four twin-gunned turrets backed by 8 x 127mm guns in a similar turreted arrangement. An additional 6 guns were of 25mm caliber (Type 96 series) for air defense and 12 x 610mm torpedo tubes were also carried. Armor protection reached 3.9" at the belt and up to 2.6" along the deck. Six floatplanes were carried for Over-the-Horizon (OtH) work, launched by a pair of catapults and made recoverable by an onboard crane. The typical crew complement numbered 874.
Installed power was from 8 x boiler units feeding 4 x Gihon geared turbines developing 152,000 horsepower and driving 4 x shafts. Speeds reached 35 knots in ideal conditions and the vessel could range out to 8,000 nautical miles.
Chikuma was ordered in 1932 and saw her keel laid down on October 1st, 1935. Launched on March 19th, 1938, the vessel was commissioned into service on May 20th, 1939.
Both IJN Tone and Chikuma were participants during the Japanese Attack on Pearl Harbor on December 7th, 1941 and the latter then took part in the invasion of Wake Island (December 8th - 23rd, 1941). From there she provided cover and support for various IJN operations throughout the Pacific Theater. She followed this up by lending her impressive firepower in the pivotal Battle of Midway (June 4th - 7th, 1942 which ended as a decisive American victory - and the loss of four important Japanese carriers.
Following this defeat, the warship took part in the Battle of the Eastern Solomons (August 25th - 25th 1942), the Battle of Santa Cruz (October 26th, 1942), the Battle of the Philippine Sea (June 19th - June 20th, 1944) and, ultimately, the Battle of Leyte Gulf (October 23rd - October 26th, 1944) where she would meet her end.
She was struck by an American aerial torpedo (TBM Avenger warplanes from USS Manila Bay) along her stern port side on October 25th, 1944 which disabled propulsion and steering while reducing speed. Two more torpedoes then followed and caused massive flooding. Additional airpower arrived to land two more portside torpedoes into Chikuma rendering her all but useless. She was then scuttled and what survivors there were to be collected were taken up by IJN Nowaki. On October 26th, American warships arrived to sink her in full and her name was officially struck from the Naval Register on April 20th, 1945.
Her sister, IJN Tone, was herself doomed on July 24th, 1945 when sunk by an American air attack near Kure.