Tatsuta and Tenryuu were the first new light cruisers for Japan while Houshou was the first aircraft carrier for Japan. Thus the learning curve.
Houshou was the first ship in the world to be built as an aircraft carrier instead of being refitted into one. There were some earlier ships that came out of their drydocks with wooden platforms replacing gun turrets, but Houshou was that first "full flattop" with dedicated hangar space.
Fufu—She constantly followed me and asked "what is the difference between light cruiser and me?"FufufufuPlease, give me a break......Tatsuta-san, please give us more details about that!!Houshou-san was very cute back then when she was constructed, you see.