 The Sovetsky Soyuz @-@ class ships devoted a total weight of 23 @,@ <unk> metric tons ( 22 @,@ 938 long tons ) to armor protection , a slightly greater weight than that of the larger Japanese Yamato class ( 23 @,@ 262 metric tons ( 22 @,@ 895 long tons ) ) . Their armor was intended to resist 406 mm shells and 500 kg bombs , specifically shells fired from forward bearings between 35 ° and 50 ° from the centerline . This led to the very unusual situation where the armor belt thickened toward the bow to compensate for the narrowing of the ship near the forward magazines , which had to be compensated for by thicker armor . The belt was 148 @.@ 4 meters ( 486 ft 11 in ) long and covered 57 % of the total waterline length . It was inclined 5 ° to increase its resistance to flat @-@ trajectory shells . Over the machinery spaces it was 375 mm ( 14 @.@ 8 in ) thick and increased in steps until it was 420 mm ( 17 in ) thick over the forward magazines . It was 380 mm ( 15 in ) over the rear magazine . The belt armor was carried forward of the magazines at a thickness of 220 mm ( 8 @.@ 7 in ) and terminated in a steeply sloped ( 30 ° ) transverse 285 mm ( 11 @.@ 2 in ) bulkhead that reduced to 250 mm ( 9 @.@ 8 in ) at the lower deck where it was continued down to the inner bottom by a 75 @-@ millimeter ( 3 @.@ 0 in ) bulkhead . Forward of this bulkhead was a 20 mm splinter belt that continued all the way to the bow . The main armor belt dropped down to the main deck from the upper deck abreast the aft turret to reduce weight . This " step " was protected by 180 @-@ millimeter ( 7 @.@ 1 in ) plates . A 365 @-@ millimeter ( 14 @.@ 4 in ) transverse bulkhead separated the rear turret and the ship 's sides . The main part of the armored citadel was closed off by a 230 mm forward bulkhead and a 180 mm ( 7 @.@ 1 in ) rear bulkhead , both of <unk> armor . <unk> armor 25 mm ( 0 @.@ 98 in ) thick covered the upper portion of the citadel . 
