Dan Reilly The Great - A surrender will be carried out alright but it won't be in a Chinese rail car. That's so 1918. No, the surrender will be carried out in a(n) *spoiler
Airship
Paul MacQ - The USSR's reaction is hostile denouncing the "Western Imperialism" as "greedy and grasping" and attack the Japanese and Manchurians as "Yellow running dogs of oppressor capitalism." In fact Stalin is so concerned that he sends one of his best Generals, a certain Leon Trotsky (not that he doesn't have his own reasons!) There will of course be a section on lessons that the Air Force learned from the KMT expedition but the time for that is still later.
Nivek - Thanks Nivek. America is quite friendly towards the KMT and the Chinese regime due to their extensive contacts. The Americans are especially friendly towards T.V Soong and the other Soong's seeing T.V as the next president of China... Time will tell whether they would be correct
You'll find out in this update whether or not you're right about the Europeans

Or will you?
Don't be too sure that the "Left" will be purged. There's a reason why they call the partnership between Chiang, Wang and Soong the *spoiler*
"Holy Trinity."
Thanks again for your kind feedback and comments.
Brancaleone - Yep - and that's precisely what happens...
Dan Reilly The Great - I wouldn't be so sure about that - a more assertive, some would say "belligerent" China might kick off an earlier rearnament - if not for the French and the British then for the Kiwi's and Aussies. The Anti-Chinese phobia IOTL was bad and real enough with a weak and essentially broken China - imagine how bad it'll be with a unified, assertive and strong China.
Thanks to everyone for their comments and feedback! Much appreciated!
Whodunnit? An explosion mystery tour
To say that the attempted assasination attempt against Sun Yat-sen and the top circle of the Kuomintang was a significant attempt is a violent understatement. It was perhaps, the defining event of the Northern Expedition - what had been a walkover to a coronation party became an uphill struggle against powerful foreign forces. What was an all but invetiable triumph suddenly shattered into broken dreams and painful memories.
And to think that - in theory the assasination had failed. None of the intended targets were actually killed. Nevertheless, the Kuomintang was significantly wounded - even crippled by the event. The paralysis of the Kuomintang post the "Nanking Affair" (as the assasination attempt would be referred to) was symbolized by an increasingly frail and senile Sun Yat-Sen.
But who was behind the assasination? To this day, who was behind the actual assasination is still one of the world's leading mysteries. Much ink has been spilled in countless reports commissioned by one party or the other to exonerate their faction or alternatively blame others. Essentially the problem with determining the origin of the assasination lies in the fact that a lot of parties had a lot to gain, and had gained from the assasination leading to a myriad of possible suspects.
Suspect 1: Emperor Zhang Zoulin, Protector of Manchuria and Mongolia
The first, and most obvious were the Manchurians. Zhang Zhoulin and Yan Xishan both had reasons to conduct an assasination attempt on the KMT. They had the contacts within China to make it happen and the fact that the assasination was botched suggests that it was not conducted by a professional foreign intelligence agency. In the Treaty of Beijing the Manchurians had gained recognition, a demilitarized zone between the two powers and Yan Xishan even managed to have his personal possessions returned. The Manchurians had gained - although perhaps not immensely but they had reason enough to assasinate the KMT leadership even without material gain.
Suspect Two: Du Yuesheng or "Big Eared Du"
The second suspect was Du Yuesheng "Big Eared Du." Du had conveniently been absent from what was a major speech and his men took several leading figures of the regime who were in Shanghai for their own "safekeeping." - including the Ailing and Meiling Soong, H.H Kung and a host of other figures. Uniformed groups wearing the KMT uniform (where there were no KMT troops in Shanghai as part of the Agreement) also aroused suspicion. Du had a lot to gain from a power vacuum caused by the assasination of the top level of the KMT, perhaps even taking control himself. Nevertheless, despite the assasination failing, Du had gained significantly. The demilitarization of Shanghai which forbade China to station troops meant that his authority in Shanghai could not be challenged by the KMT government. Sun's increasing decline into senility had also caused a vacuum in which the KMT government was all but paralyzed - leaving Du's gangster men to fill the void.
Suspect Three: The Japanese
The third suspect were the Japanese. They had gained from the peace deal, securing the demilitarization of key borders and securing indemneties that was all out of proportion to the damage done by the mobs. The assasination had also signficantly weakened China - and a weakened China was one of the tenets of Japanese foreign policy.
The fourth suspect were the Western Powers themselves. However, there is little to substantiate this view. Although the KMT was being seen as an increasing threat - there was no concrete policy laid out in the foreign offices of France and Britain and their greediness in the Treaty of Beijing was opportunistic rather than planned.
Suspect Five: Chen Duxiu - The General Secretary of the Chinese Communist Party
The fifth and final suspect were the Chinese Communists under the leadership of Chen Duxiu. This is however, highly unlikely as they were as taken aback as the rest of China was and failed to seize the moment in any meaningful way. Furthermore, Chen Duxiu was a hardline orthodox communist who obeyed the line from Moscow without question. The line from Moscow was that Chen and the Communists would follow and prop up the KMT without question while massively infilitrating it from within. But there would be no splits and absolutely no assasination attempts. In fact the Chinese Communist Party were the first to rally around the KMT banner when it was discovered that Sun had lived.
Regardless of who had prepared and backed the assasination attempt and the fact that it had actually failed, the effects were catastrophic for China and the Kuomintang. There is a reason why the final, post-Nanking incident years of Sun Yat-sen's life are called the "lost years" or the "black years."
Next Update:
1928 - From bad to worse.
Feedback and comments always welcome (in fact actively solicited!)