The class, consisting of Agano, Noshiro, Yahagi, and Sakawa, are light cruisers designed to replace the 5,500 ton standard light cruisers of the IJN during WWII. With technologies learned from the experimental cruiser Yubari, the class' primary role is reconnaissance and thus are fast, lightly armored and armed.
The set includes Agano[1943] (port/topmost ship) and 3x Yahagi to represent Noshiro and Sakawa as well.
http://en.wikipedia.org/wiki/Agano-class_cruiser