was the lead vessel in the heavy cruisers, active in World War II with the Imperial Japanese Navy. These were the largest cruisers in the Japanese fleet, and were intended to form the backbone of a multipurpose long-range strike force. Her sister ships were , and . Takao was the only ship of her class to survive the war. She was surrendered to British forces at Singapore in September 1945, then sunk as a target ship in 1946.
Background
The Takao-class ships were approved under the 1927 to 1931 supplementary fiscal year budget, and like her sister ships, was named after a mountain. Mount Takao (高雄山) is located outside Kyoto and is not to be confused with the similarly named Mount Takao (高尾山) located outside Tokyo, or the city of Takao (高雄, Kaohsiung), in Taiwan.
Design
thumb|left|The bridge of Takao the year she was commissioned, 1932
The Takao-class cruisers were an improved version of the previous design, incorporating technical elements learned with the development of the experimental light cruiser . They had a distinctive profile with a large, raked main funnel, and a smaller, straight, second funnel. Intended to address issues with the Myōkō class, the Takao class had thicker armor, dual-purpose main guns which could be used against aircraft, and torpedo launchers moved to the upper deck for greater safety. However, as with its predecessors, the Takao class was also top-heavy.
The Takao class displaced . Takao was long, with a beam of , draft of and were capable of 35.25 knots. Although the first ship in her class to be laid down, Atago was actually completed two months earlier.
All of the Takao class were assigned to the Yokosuka Naval District, forming Sentai-4 of the IJN 2nd Fleet, and trained as a unit during the 1930s. She was captained by Captain Chūichi Nagumo from November 1933 – 1934, Captain Eiji Gotō from November 1934 – 1935, Captain Takeo Takagi from December 1936 – 1937 and Captain Tadashige Daigo from December 1937 – 1938. During this time, issues with their stability and seaworthiness due to the top-heavy design became evident. Takao and Atago were rebuilt at the Yokosuka Naval Arsenal between 1938 and 1939, resulting in an improved design: the size of the bridge was reduced, the main mast was relocated aft, and hull bulges were added to improve stability. Maya and Chōkai were not modified as extensively, and can be considered mistakenly as a separate class.
In April, she participated in the unsuccessful pursuit of the Doolittle raid task force.
On 2 May, Takao assisted in rescue efforts for the seaplane carrier , which had been torpedoed by the US submarine off of Omaezaki. Takao rescued 471 crew from the sinking ship . When the mines exploded, they blew a hole. Several compartments below the lower deck were flooded, including two ammunition magazines, the main gun plotting room and the lower communications room.