南雲忠一
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. After rebuilding was completed, "Takao" and "Atago" patrolled off the coast of China in 1940 and early 1941.