HMS Indefatigable was one of two Implacable-class aircraft carriers built for the Royal Navy (RN) during World War II. Completed in 1944, her aircraft made several attacks that year against the German battleship Tirpitz, inflicting only light damage; they also raided targets in Norway. The ship was transferred to the British Pacific Fleet (BPF) at the end of the year and attacked Japanese-controlled oil refineries in Sumatra in January 1945 before joining the American forces in March as they prepared to invade the island of Okinawa in Operation Iceberg. Indefatigable and the BPF joined the Americans in attacking the Japanese Home Islands in July and August. Following the end of hostilities she visited ports in Australia, New Zealand and South Africa.

Tirpitz was the second of two Bismarck-class battleships built for Nazi Germany's Kriegsmarine (navy) prior to and during the Second World War. Named after Grand Admiral Alfred von Tirpitz, the architect of the Kaiserliche Marine, the ship was laid down at the Kriegsmarinewerft in Wilhelmshaven in November 1936 and her hull was launched two and a half years later. Work was completed in February 1941, when she was commissioned into the German fleet. Like her sister ship, Bismarck, Tirpitz was armed with a main battery of eight 38-centimetre (15 in) guns in four twin turrets. After a series of wartime modifications she was 2000 tonnes heavier than Bismarck, making her the heaviest battleship ever built by a European navy.