Following Japan's withdrawal from the London Naval Treaty, all four underwent a massive second reconstruction in the late 1930s. Following the completion of these modifications, which increased top speeds to over 30 knots (56 km/h; 35 mph), all four were reclassified as fast battleships. | Following Japan's withdrawal from the London Naval Treaty, all four underwent a massive second reconstruction in the late 1930s. Following the completion of these modifications, which increased top speeds to over 30 knots (56 km/h; 35 mph), all four were reclassified as fast battleships. |