The Katori class were designed to be training cruisers. The Kashima and Katori were ordered under the 1930 Supplementary Program / 1937 Supplementary Program.
The bridge was designed so it could hold more midshipmen and there was a variety of equipment to allow for training.
Once Japan started the war, they were used as flagships for submarine and convoy escort units.
In the 1942 Program there were to be four more Kashii class cruisers to be built but they were cancelled. They were to be armed with the 3.9" L/65 as the main guns.
The catapult was located amidships for the single aircraft carried.
There were turbines and diesels that powered the Katori class. This allowed for engineering officers to learn both types that were used in the Imperial Japanese Navy.