The Ship Model Forum

The IJN used metric system measurements.

Yes... but there are some quirks to that, such as the 14" battleship guns that were called 36cm, though they really were true 14" diameters; old construction, a holdover from their British origin true... but then there's their WWII heavy cruiser guns which were officially designated as a 20cm/50 weapon, and sometimes a bore diameter of 20.3cm is stated, but were in fact 20.32cm, or precisely 8.0" to max out the gun size to treaty limits. The Akagi's 12cm weapons followed a series of earlier 4.7" guns that were redesignated as 12cm after Japan went metric, and if they were able to keep firing the same types of projectiles then they probably matched the diameters of the earlier guns.

- Sean F.

All I know is that the Japanese documentation always uses metric measurements.

I`m about to start building the hasegawa 1:700 Akagi and I try to collect all reference material what I can find. I was just wondering how these model companies can design an accurate model from a few old photographs? They know the basic dimensions but, surely lots of details unseen on them. Is it just an educated guesswork or are the plans existing in some japanese naval libraries? I`m not expecting to find them anywhere , asking just for curiosity . Tanks , Planes are easy to research because you don`t have to dive 5000m in the pacific ocean to find them

There are plans out there. Many are published, including those for Akagi. She was very well documented.