ok so we've established no second russo-japanese war.
How does China evolve?
Would it continue on into Warlordism or would it unite and if so by whom?
Some say the Japanese won the war for Mao but is that true?
If the republic wins the war can they remain united?
Would the Soviets setup a "Taiwan" in Manchuria?
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Yeah, would Chiang then preside over a fascist-lite version of the PRC?
Landless warlords like Zhang Xueliang and Feng Yuxiang are going to be sidelined fast, while the warlords in the periphery (Shanxi, Guangxi, Yunnan, Gansu) are probably going to last longer, as those places were the backwater part of the country and are no match to lucrative provinces like Hebei, Sichuan, Guangdong and Lower Yangtze, all of which are firmly under Chiang's control.
Socially, Taiwan-style land reform will take place, namely converting large holdings into stocks of state-owned companies and bonds at gun point, both appeasing the peasants and removing a layer of control. Election would likely be held at county-level and below, not enough to undermine the central authority, but enough to undermine provincial warlords. Parliament and provincial councils
may be elected, but will be no more than Putin's Duma. Peaceful, unarmed dissidents will likely be tolerated, seeing how Chiang didn't purge Wang Jingwei despite being rival for decades and the latter had not a soldier at his disposal, and the expulsion only came when he tried to negotiate a peace with Japan on his own accords.
In Xinjiang, even if an ambitious man like Sheng Shicai is appointed, Chiang will have his hands free to deal with any out-of-line behavior so it's going to be more akin to a central controlled province than a warlord domain. A few divisions will "restore order" in Tibet but the young Dalai Lama will be kept as a puppet preaching peace and order. Local social structures probably won't be touched until a grassroot social reform movement forms, then the KMT will grant their benevolence to the Tibetan people and further penetrate Tibet by removing local barons.
Merchants and entrepreneurs will be supported by the state, as they can generate large taxes without threatening the KMT authority. Inequality may surface after a few decades, but in the short term, peace and prosperity will cover it up like the PRC now.
Unless there's a major fuckup when undermining Zhang and Feng that results in a second round of civil war, China will very likely be better than IOTL all the way to Chiang's death in the '70s
After that, it's quite unpredictable. Chiang Ching-kuo was a Trotskyist in his youth IOTL, but became a generic right-wing despot when he took over in 1975. But if life hadn't denied his chance to act left-wing, and that the KMT is no more pro-capitalism than pro-Chiang dynasty at his inheritance, China might take a great turn left, but not too close with Stalinist USSR. In any case, by this time, the warlords will have been dead or retired (maybe expect the Ma dynasty, but they aren't much of a threat on their own and they held remote backwater places anyway), so civil war is no longer a problem, but my guess on further socioeconomic developement are likely to be no more than ass-pulls.