Development of the Mogami-class cruiser dates back to the early 1930s, when the IJN launched its development as part of a naval rearmament program. Wishing to substantially strengthen their navy’s cruisers, the IJN high command ordered for a new design to be drawn up which would practically reach the very limits of the London Naval Treaty in effect at the time.

The new warship was initially set at a displacement of 8,500 tons and was to be armed with fifteen 155mm guns, spread across five triple turrets. However, even at the design stage it was already clear that the real displacement would significantly exceed this limit and would be around 11,000 tons so it was decided to conceal the true data. In December of 1934, Japan denounced the Washington Agreements, and refused to sign the Second London Treaty in January of 1936. As a result, in the period between 1939 and 1940 all cruisers of the Mogami type underwent reconstruction, in which the main weapons were replaced by ten 203-mm guns in five turrets, the ships were then formally reclassified as heavy cruisers.

Nonetheless, Mogami-class cruisers raised concerns with other naval powers, some simply dismissed their design specifications as being false, while others, such as the U.S., began building counterparts of their own. Four Mogami-class heavy cruisers took part in several major operations during WW2, including the Battle of Midway, Leyte Gulf and many others. All ships of the class were lost in combat between June 1942 - November 1944.