I think adding Thailand to Japan as a full subtree would be an excellent way to bring Japan in Line with China in terms of current and Future TT depth.
This would set a precedent for being able to loop in more SE Asian Subtrees to both China and Japan in the future. This would also allow the US to take SK as a Subtree without aggrivating quite as many people who want to see it added to Japan for balance purposes.
I think all branches of the JP TT would greatly benefit greatly from Thailand being added as a Subtree.
I think US TT doesnt need sub tree, it has enough vehicles to be added in future to even form another branch. I know many would disagree with me, but SK should be part of United Korea tree which would include both SK and NK ( like China combining ROK and PRC), I’ve seen concepts of ground, air and heli trees, and they all seem legit to be a stand-allone tree starting at rank 5 ( just like Israel at rank 4 ). I know there are a lot pattons there and Magach situation could happen again(((, but regardless of that there are just too much domestic IFV, TD and MBT designs to fit all in one small sub tree.
Sorry for my english, I’m not a native speaker.
Having a Thai Subtree in the Japanese TT should be fine, maybe paired with (postwar) Philippines as well to further fill up the later tiers (Tier IV onwards) of the Japanese TT, the earlier tiers don’t need as much help but it will still be nice for variety sake
I think Thailand should not join as a sub technology tree of Japan, because it has almost no tanks developed/manufactured by itself, but buys foreign trade tanks from other countries. Especially after the Cold War, Thailand has a large number of tanks made by China. Imagine that if you see the tanks that should have been obtained by China in the Science and technology in Japan technology tree, this is not appropriate, so Thailand should act as a Southeast Asian line with other Southeast Asian countries, Alternatively, the vehicles purchased by Thailand from other countries can be sent to the countries that sell them like 69IIG.
Maybe it doesn’t need to have every single vehicle in Thai armed forces’ history, just one that’s iconic or historic enough to see and feel like it represents Thai armed forces’ identity/uniqueness especially during WW2 and Cold War periods, such as M60s, F-5s, or Commando Stingray (Which Thailand is the only foreign user.) similar to how Finnish Sub tree works in Sweden Tech Tree
(Sorry for many edits, just wanted to clarify things)
Even Türkiye, a country with a certain military industry capability, is assigned to different TTs. Thai vehicles only need to go to their production countries.
Taiwan is an integral part of China, and Taiwan’s F16 is purchased by Taiwan. Regarding your question. Firstly, Thailand is not part of Japan’s territory, and after World War 2, Thailand did not purchase any tanks or aircraft from Japan! Second: Japan does not have any Chinese equipment, so it is unreasonable to put the Chinese equipment purchased by Thailand on the Science and technology in Japan tree! All Chinese players will not agree! And third, this is the most important point: Taiwan is an integral part of China, while the the People’s Republic of China belongs to China, and the Republic of China also belongs to China. Their relationship is a normal regime change. They are not two countries!
And secondly not EVERY vehicle needs to be added just the ones that help fill the needs and gaps of the TT and the ones that make a bit more sense. So chinese stuff, Gripens for example don’t need to be added those can go to the respective TT
But I can’t find any aircraft or other vehicles purchased by Thailand during World War II other than Japan (perhaps due to my lack of comprehensive information). However, during the post World War II, Thailand had the same number of Chinese and American cars, but most of the cars in modern Thailand were Chinese, which actually lost Thailand’s integrity as a sub technology tree
As I said, the the People’s Republic of China belongs to China, and the Republic of China also belongs to China. They are just normal regime changes and essentially belong to one country! Not two countries!