Not entirely unique. Hyuga (except for it's not going to carry aircraft - heh) is a functional duplicate of the Italian Giuseppe Garibaldi
Similar layout, but some differences. The Hyuga and Ise are quite a bit larger (18,000 tons vs 13,800 tons) than the Giuseppe Garibaldi. They are also have a heavier missile armaments with 16 VLS tubes. Interestingly the Giuseppe Garabaldi carries 16 AV-8s or 18 helicopters. Ise and Hyuga only have a compliment of 14 helicopters. Italy like Japan was forbidden from operating aircraft carriers after WWII. And build the Giuseppe Garibaldi in 1981 to get around the same restrictions. The Italians changed their constitution (I think in the late 80s or early 90s) and built a larger 30,000 ton ship. However it is still a mixed use vessel rather than a single use aircraft carrier.