The objections of Japan's 'battleship admirals' to the carrier conversion of older battleships Owari and Tosa were only slightly offset by the carrier-to-battlecruiser conversion of Aratama. The 'gun club' felt slighted again when a mighty Satsuma-class battleship under construction was sacrificed and stretched to make the CV Yonaga. Still, the extra speed and size attained could work for a battleship, too, the 'gun club' surmised. The huge 20"-gunned Satsuma was almost done, now, and another of its kind started. Four large battleships, slightly smaller versions of Satsuma with triple 18"gun turrets, rather than twin 20", were authorized, and two had been started. Now, though, the Navy officials were leaning towards carrier conversions for those as well.

Afraid that their battleship building program might be altogether curtailed, the 'black shoes' proposed to combine the materials set aside for the upcoming Settsu and Yamato to make a super battleship of nearly 90,000 tons, and to dedicate the leftovers for a light carrier conversion to appease the aviators. The resulting BB Yokozuna had the stretched hull and machinery of Yonaga but with additional bulges and tonnage that reduced speed. The 18"-gun manufacturing program was in full swing after minor setbacks, but the 20" program had faltered due to a massive earthquake. Although two twin 20"-gun turrets were available, the three needed for Settsu or the four proposed for Yokozuna were unobtainable. One possibility was for a split battery fore-and-aft of 20" in front, and 18" in the stern. Though the 'black shoes' were reluctant to reduce the caliber of armament, especially in light of the German Führer project, the more pragmatic and timely approach put four triple 18" turrets on board. Japanese divers had recovered the fire-control radar apparatus from the sunken South Dakota in shallow waters, and amazed Japanese technicians cobbled together a system for Yokozuna that worked, at least in practice firings.

The Satsuma became known in the Japanese press as 'Sumo' and, of course, the Yokozuna was the 'Grand Champion.' Together they formed Battleship Division 1 as the Philippines was being threatened. On their only sortie together, they took a pounding from U.S. aircraft in the Sibuyan Sea. Seeming to turn back, they and their cruiser consorts reformed and, at night, got among the escort carriers and Marines landing at Leyte and thoroughly disrupted the invasion attempt. Lightly plated American ships were sieved by armor-piercing 18" and 20" shells that detonated after passing through their hulls. As 'the world wonder[ed]', Admiral Halsey dispatched Washington, Indiana, New Jersey, and Iowa to intercept the Japanese force at the San Bernardino Strait. In the last surface action between battleships, the 'little' American battleships showered the two Japanese giants with 16" shells. Indiana was sunk, and both Iowa-class ships were badly damaged, but 'Sumo' and 'Grand Champion' had been wrestled to the mat in Davy Jones' locker.