info. taken from Shipbucket forum:
This ship was designed in early 1941 for the Dai-Roku-Ji Kaigun Gunbi Hojū Keikaku (Sixth Naval Armaments Supplement Program), also known as Maru 6 Keikaku (Circle Six Program) but the plan was quickly shelved and replaced with the 1941 wartime construction program in september 1941.
the 1941 Type A cruiser was planned as an eight-ship class, 218 meters long, armed with twelve 8-inch (203mm) guns in triple turrets and twelve 3.9-inch (100mm) guns in twin turrets (the same model that would eventually see service with the Akizuki class destroyers) and a 5.5-inch(140mm) planned armour belt would have been a match even for the Des Moines heavy cruisers (at least in terms of dimensions and firepower).
However, to my knowledge no official design for these cruisers exits. So this design is purely conjectural.
with Neptun Suzuya: