Japan air - reorganized & expanded

This is a considerably expanded tech tree for the Japanese air force in War Thunder.
The general layout and structure of the tech tree currently in game is mostly intact, but some vehicles are moved in BR, rank, or branch. And of course, many vehicles have been added.

As it stands in-game, the Japanese air tree has quite a few gaps and dead space, especially from rank 4 onwards. Meanwhile, there remains an ocean of aircraft (both unique and variants) that could be added to fill these gaps, but have not been for one reason or another.
The goal then for this expanded tech tree is to show what a more properly fleshed out Japanese air tree could look like, without straying too far from the current in-game layout and structure.

When I originally started expanding the tree, I tried to limit myself to aircraft that were built and flown. For some areas however, this is simply not possible. For instance, neither Japan nor Thailand operated any jet bombers, nor many heavy bombers, making rank 4 and 5 of the bomber line impossible to fill with vehicles under these strict requirements.
Additionally, there are simply too many interesting prototype and concept aircraft out there to ignore. Personally, I have no issues with prototype or 'paper' aircraft in War Thunder, provided no properly built aircraft exists that could fill the same gap. I would rather have a few 'paper' aircraft here and there than another hundred copy-paste vehicles.
Still, I do have some guidelines for including concept or paper aircraft:
- Firstly, the concept should have really existed (no made up sources), and seriously considered. So, no UFOs drawn by a designer after a drunken night out that were instantly rejected or never thought about again, and no completely made up stuff.
- Secondly, the design must be at least somewhat realistic. This is a bit of a vague guideline, but generally it means that the aircraft should look like it could have been built and flown had the design been pursued (and/or the war not ended). As an example, the R2Y2 V1 fits this, where the R2Y2 V2 and V3 do not.
- Lastly, the aircraft should ideally fill a gap in the tech tree, either BR-wise or in terms of functionality, which cannot be adequately filled by another aircraft (as already mentioned previously). Exceptions apply, but generally I consider this the most important of the three guidelines.

As for the remaining details about the tech tree, to start, some planes have had their BRs adjusted somewhat. Most noteably, all planes above 8.0 are moved up by 0.3, to provide at least a bit of decompression. So, all BRs beyond that point assume that all other trees would receive the same treatment.
In all likelyhood, there are many more BRs that ought to be changed, both for existing and for some of the new vehicles. I do not consider myself qualified enough to accurately judge what these planes are and how they should be changed however.
If there is a plane whose BR you think should be changed, and you have good arguments for it, please do let me know.

The inclusion of rank 9 is mostly just as a joke (altough the game is probably headed that way anyway). Like many others, I do not particularly care about top-tier/modern vehicles all too much. Take any of the BRs up there with a massive spoon of salt.
Vehicles currently under consideration (but not yet placed) are visible as squadron vehicles in rank 10 of the tech tree. BRs, placements, and all that are nowhere near final for any of these.

In terms of research, I have to admit most aircraft have not had particualrly deep research put into them, and thus do not have primary sources attached. This may change over time, but will be a slow process.
Again, if you happen to have primary sources or other information on aircraft in the tree, please do let me know!

As a final note, if you have suggestions for aircraft you think should be in the tech tree, again let me know. The best way to reach me is probably through TheSnazzyComet's discord (they were the one to inspire me to make a tree like this to begin with!).

I hope you enjoy!