IJN I-361 class transport submarine (伊三百六十一型潜水艦 I-san-byaku-roku-jū-ichi-gata Sensuikan), also called Type-D submarine
I have got both the: Aoshima 1/350 I-370 - and I-365.
Most of all it looks like a torpedotube - but it is not. Maybe a sensor of a kind?
I have never seen anything like it on other submarineclasses!
I can't find any info about it, and no photo of the submarine-class below waterline seems to be available either.
Any info will be very welcome