By 1943 the Kirishima, laid down prior to WWI, was hopelessly underarmored in terms of both thickness and metallurgy. She had just enough armor to guarantee that armor-piercing shells would detonate, without being able to resist penetration. So when the Washington opened up on her at close range with 16" guns, she didn't really stand a chance. The shells easily penetrated her armored belt, some below the waterline, detonating in critical areas. By the second salvo she was already doomed.