The definition of “capital ship” was formalized in a series of naval treaties in the 1920s and 1930s. Falling into this category were battleships and battle cruisers. These ships were close to 20,000 tons displacement or heavier, with large caliber guns and heavy armor protection. Heavy cruisers, despite being important ships, were not considered capital ships. An exception to this during World War II was the Deutschland class heavy cruiser, technically a fast-moving heavy cruiser but with considerably heavier guns. The Graf Spee was an example of the Deutschland-class heavy cruiser, which the British labeled “pocket battleships.” Following the outbreak of World War II in September 1939, Hitler ordered the battleships and battle cruisers of his Kriegsmarine (German Navy) to begin commerce raiding against Allied merchant traffic.

Compared to other navies during World War II the German Kriegsmarine had few modern battleships. Limitations set by the Treaty of Versailles in 1919 meant Germany could not build a large battle fleet as it had in the time leading up to World War I. Only in the 1930s, after Hitler had come to power in January 1933, did German naval rearmament begin in earnest. Two battleships of the Scharnhorst class were laid down in 1935, launched in late 1936, and commissioned into the German fleet by early 1939.

At the outbreak of the war in 1939, battleships in the Kriegsmarine (though not necessarily yet commissioned) consisted of the pre-World War I Schleswig-Holstein, which fired the first shots of World War II by bombarding the Polish garrison at Wester­platte in the Gdansk (Danzig) harbor channel; the Graf Spee, which was scuttled by her captain when confronted by British warships in the Plate estuary off Montevideo, Uruguay, on December 17, 1939; the Bismarck, which was famously pursued and sunk in the North Atlantic on May 27, 1941, by the Royal Navy after the Bismarck had destroyed the battle cruiser HMS Hood (“Mighty Hood”), the pride of the Royal Navy; Bismarck’s sister ship Tirpitz, which was sunk while moored outside Tromso, Norway, on November 12, 1944, by high-level British Lancaster bombers; and the Scharnhorst and her sister ship Gneisenau. The latter two battleships gained notoriety when they surprised and sank the British aircraft carrier HMS Glorious off western Norway in June 1940. The Gneisenau was heavily damaged in a Royal Air Force raid in its Kiel dry dock on the night of February 26–27, 1942; its guns were removed to become shore batteries in Norway, Denmark, and the Netherlands. The Scharnhorst was sunk by the Royal Navy off Norway’s North Cape on December 26, 1943, in the last battle between big-gun capital ships in World War II.