From: The Big Nowhere
I've been doing quite a bit of research on the IJN and their building plans pre and post-Washington Treaty. This is what I have come up with for building programs. Bear in mind this was always subject to change, and accuracy can be iffy on certain items. Basically its a guide, nothing more. Also, if you have a source that can confirm or deny these, feel free to do so.
I'm still looking for info on Britain and US, so if anyone can point me to a source, please do so.
-Shokaku Class: These were to be 2 ships (Shokaku and Zuikaku) that were basically an enlarged Hosho. 12,500 ton displacement.
-Ryujo Class: Additional 2 boats planned, and at a higher displacement than Ryujo was built at. 10,000+ ton displacement.
-27,000 ton Class: Not mentioned by name, and never made it past plan/requisition phase. I have no other information at this time.
-G6 Class: Follow on to Soryu that was not approved. 1934-1937 era.
I somehow doubt all of these would have been built, especially if the Shokaku and additional Ryujo's had been completed to original design. There is also mention of 1 additional Hosho, but this is probably referring to the Shokaku class that was cancelled due to the treaty. The 27,000 ton class was requisitioned for the 1923 building plan, but not approved most likely due to the Treaty.
-Kii Class: Four ships, ~42k tons, 5x2 16in/45 guns. Kii, Owari, No 11, No 12
-No 13 Class: Four Ships, ~48k tons, 4x2 18.1in/45. No 13, No 14, No 15, No 16
No other Battleships scheduled. The Kii's along with the No 13s would have made up the 8 BBs of the 8-8 plan. Nagato, Mutsu, Ise, Hyuga, Fuso, Yamashiro most likely to reserve or decommission.
-Kaga Class: Two Ships, ~40k tons, 5x2 16in/45. Kaga, Tosa
-Amagi Class: 4 Ships, ~41 tons, 5x2 16in/45. Amagi, Akagi, Takao (Akitaka), Atago. Amagi destroyed by Earthquake 1 Sept. 1923 and scrapped.
Under the 8-8 plan, the above six ships plus 2 of the Kongo class retained, 2 Kongo class to reserve. With loss of Amagi, an additional Kongo may have been retained.
Additional Note on the BB and BC classes. The No 13 Class is often listed as both, but in truth it was larger and more heavily armed/armored than the Kii Class, which is why I rate them as BBs.
-Sendai Class: 1 Ship, Kako, cancelled in the slip.
-Scout Cruisers: 12 planned, 8 Cancelled. 4 that were completed are the Takao Class from WWII.
This Category is about as clear as mud. While it is easy to see the 1 cancelled Sendai class, the 12 scout cruisers are not specified. The 4 that show completed are also in for a renaming, as they carry some of same names as the Amagi Class BCs. Complicating matters are the facts that 1) scout cruisers can mean anything from the super light Kuma, Nagara, Yubari, Sendai Classes to the 'heavy cruisers' as we know them; 2) the distinction between CA and CL did not exist, 3) the trend in building had been to very light Scout Cruisers with the heavier Protected Cruisers being more akin to mini-battleships.
-Kamikaze Class: 20 planned, 9 Completed. The 11 cancelled had not been assigned names yet, canceled before order due to the treaty.
-Wakatake Class: 5 Canceled. Shion, Basho, Omadaka, Kaou(?), Nadeshiko(?) ? means I am unsure of actual name/possible mistranslation.
The cancelled DDs were apparently done in favor of more heavily armed designs to get the most bang for the buck.
-L2, L3, and L4 Classes: Up to 25 boats canceled. Need more details.
-'Minelaying' Submarine Class: 2 Canceled
-'Supply' Submarine Class: 4 canceled
Another clear as mud category. As noted, need more details to firm this up.
-W1 Minesweepers: 3 Canceled.
-Yeayama Class: 16 canceled. Described as 'Netlayer' and 'Minelayer'.
-Various Classes: Netlayers, 11 Canceled.
-Various Classes: Gunboats, 6 Canceled.
-'Spy Ship': Not specified, though tonnage given as 10k.
-Erimo Class: 1 oiler canceled.
-Mamyia Class: 1 supply ship canceled.
Again, short of details.
Keep in mind these are the changes between the 1923 plan and what was completed by 1927, with the exception of the G6 Class carriers which I included as a 'bonus'. Any information that can correct errors or omissions would be greatly appreciated.
Distant Worlds Fan
'When in doubt...attack!'