The Unryu class ships were similar in design to the Hiryu. They were ordered under the 1941 Program.
Two elevators were installed in the flight deck.
There were two hangars.
The aviation fuel had concrete surrounding its storage tank.
The Amagi, Ikoma, Kasagi, and Unryu had the engines originally allocated for cruisers installed.
The Aso and Katsuragi had destroyer turbine engines installed due to the lack of more powerful engines.
In the 1942 Program hull number 800 was ordered but it was later cancelled. In the 1942 Modified Program hull numbers 5002, 5005, and 5008 - 5015 were ordered but all were later cancelled.