These Tamiya 1/700 kits are lovely, though expensive and I have to be "in a naval zone" to have a go at them. The IJN submarines here are double the scale (reduced) of the Revell U-Boats (see previous posts) but in reality were twice the tonnage, so length wise they are not too far off. Unlike U-Boats the Japanese Submarine Cruisers were designed to be the "eyes of the battle fleet".
Japanese Cruiser Submarine: I-16 with Kaiten midget submarine (see below). It took part in the Pearl Harbour operation (see below):
Japanese Cruiser Submarines I-58, he deck bubble at the front housed a float plane, again ideal for the "eyes of the fleet" role envisaged for it (see below). This is the submarine that sank the USS Indianapolis in 1945 but after it had delivered the second atomic bomb.
I chose the simple underwater assembly, there were more hoists, railings and spars to add (as well as a float pane) for the surface cruising mode.