The forward conning tower had 350 mm-thick sides and a roof that was 200 mm-thick. The rear conning tower was less well armored, with sides and a roof that were only and 50 mm thick, respectively. The gun turrets for the main battery had thick faces, 200 mm thick sides, and 150 mm thick roofs. The barbettes that held the 28 cm gun turrets were also heavily armored; the sides were 350 mm thick and tapered down to 200 mm on the centerline, where they were shielded by the gun turrets above. The faces of the 15 cm turrets were thick, with thick sides and 50 mm thick roofs. The 10.5 cm gun mounts were equipped with gun shields. All of this armor was KC steel.