Kawachi was a mid-war experiment in 'large cruisers' much like an enlarged Chichibu (or USS Alaska). The twin 14" guns were not taken from the various older battleships, but was a newer, faster-firing model that it was hoped would equip several new 'cruisers' during the war and re-equip the elderly battleships as well. Japan's overstretched war economy made only enough new guns to equip the Kawachi, but she was a suitable replacement for the loss of the Kongo-class fast battleships around Guadalcanal.

Though she sank two American cruisers in a sea battle off the Komandorski islands, aerial bombs nearly wrecked her, and she limped back to Japan. With only one original turret working, she was partially reconstructed and in a reversal of original intentions, given two old 14" turrets taken earlier from the converted Ise for the "Last Sortie" of the Imperial Japanese Navy. Against an unstoppable onslaught of carrier attack planes, Kawachi disappeared in a huge explosion.