Just a tiny point about the numbers in screen shots. The gothic numbers seem a little out of place. Would it be possible to use the Japanese characters?
The signatures on any documents for promotion etc would look better with a "hanko" seal on them.
Sorry to nitpick and I hope you don't get the wrong impression
This is truly awesome stuff!
PS Hope you overcome the launching planes / minisub problems. Managing to get a shore bombardment mission would be great too!
PPS Assorted photos from Japanese archives being searched for now. Crew of three native Japanese on it!
PPPS Re: ship traffic, off all the major rivers mouths near Japan: literally swarming with fishing boats, sampans and small commercial craft. I watch the trawlers and fishing boat fleets everyday at the entrance of Tokyo Bay, scuttling out of the way of RORO and container ships. Sailing on the surface within 10km of the coast near the four main islands without literally bumping into one would be almost impossible. On the upside not many were fitted with "rajios" so the IJN wouldn't know until they reached port.