Hi humble.

IJN warship had 'nameing rule'.
small CV '~~you' series are 'CV modefied from civirian ship'.
Taiyou -Big hawk- was modefied from Kasuga-maru (17000ton Passenger liner for Japan~europe)
Kaiyou -Sea hawk- was modefied from Aruzenchina-maru (12755ton passenger liner for Japan~south america)
Taiyou had 2 sister.
''Taiyou, Chyuuyou, Unyou'' was same class.
because, they were modefied from same 17000ton class passenger liner ''Kasuga-maru, Nitta-maru, Yahata-maru''.
another '~~you' series small CV....
Shinyou -God hawk- was modefied from Scharnhrst@( 18184ton German passenger liner)
WW2 started when she came to Japan,
She could not return to her motherport at Germany.
so, IJN bought@her from german owner,and modefied for IJN CV.
can u undertand?
sorry my poor English.

thnx.