There really was an Imperial Navy auxiliary transport ship named Rio de Janeiro Maru From 1941 to 1943 she served as an auxiliary submarine tender.

If you think I'm making this up, just Google it yourself!

Operates with i-8 and Yura in the 5th Submarine Squadron and Southwest Area Fleet

Hacchan is international, so I've been fluently talking with her in her foreign language.

Hacchan, you speak German

Kancolle Trivia!

Ta-da!