That’s a layout of Japanese ships in 1941, not showing all they had during WWII. They had more submarine aircraft carriers than any other navy, the I-400 class being the largest ever built until the 1960’s by the U.S.A. They could surface, launch planes and then submerge again. I think the U.S.A. sunk a confiscated I-400 sub off Hawaii after the war. Too bad they didn’t save it as a museum piece.
True— this is what western journalists knew Japan had in Dec of 41. I noticed the graphic is missing the Shokaku class and the Yamato (secret at the time) among others. The spelling of the ship names is also strange. Around the time that Japan joined the Axis, it seems they changed the translations of their words to German (i.e. Tokyo became Tokio, Fuso became Huso, Kirishima became Kirisima, etc).
Yes, Japan had toyed with the idea of using the I-400 class late in the war to launch air raids on the US mainland, but were hesitant fearing US revenge (over and above the napalm raids).