So I know the Japanese never really had an organized plan as for the ultimate fate of conquered China. they didn't think much about what they would do after they won. However, the invasion of the European Colonial holdings in SE Asia was much better organized and planned, with strategic goals in mind. I have heard poorly-supported theories elsewhere that the Marco Polo Bridge incident was deliberately created by either Hideki Tojo or field officers near Peking for no other reason than to act tough and win glory, and the Emperor Hirohito really didn't want war with China, ever. After the Incident, however, his hand was forced. This supposedly created a very poorly planned, unwinnable war with no long-term thinking involved. Is there any truth to this theory?
Short answer: no. In fact, Japanese field officers at Marco Polo Bridge and the Beijing-Tianjin region attempted to limit the incident to a local affair. Local Chinese and Japanese forces agreed to a cease-fire on 11 July 1937, but by then the Chinese decision to to send three divisions northwards had effectively made moot any effort to de-escalate the situation. For a longer answer, see here.
The Emperor Hirohito was never a supporter of a general war with China. In 1936, he firmly told the army Chief of Staff that:
I will never allow the Kwantung Army to cross the Shanhaiguan pass into China proper.
Shanhaiguan being the traditional entry point through the Great Wall to the Beijing-Tianjin region. However, Hirohito also acknowledged that he had little control over the army in a conversation two days later with the navy Chief of Staff:
There were instances that the army did not listen to what I said. This is the consequence of the lack of control and failure of a subordinate to execute the will of a superior.
In his recollections in 1946, Hirohito further expanded on his thinking during the July 1937 Crisis:
Sino-Japanese relations were such that war could have broken out at the slightest provocation. Therefore, I summoned War Minister Sugiyama and Army Chief Prince Kanin, because I somehow wanted to reach a compromise with Chiang Kai-shek.
It so happened that the Kanchatzu incident (a skirmish between USSR and Japanese troops on the Amur River in June 1937) broke out along the border in northern Manchuria, and the incident was used to camouflage [the purpose for] my audience with them [Sugiyama and Prince Kanin], but in fact I summoned them to hear their opinions about [our] China policy.
If the army agreed with my opinion, I thought I would ask Konoe to compromise with Chiang Kai-shek. Manchuria is countryside [i.e., very rural] and an incident there would not have developed into a serious crisis, but in case of an incident in Tianjin or Beijing I was afraid that the Anglo-American powers’ interventions would definitely escalate into a clash between them and us...The chief of the General Staff and the war minister were of the opinion that an incident in Tianjin would be over within a month, if we struck the first blow [against the Chinese]. I realised that their opinions were different from mine, and regrettably I did not bring up the question of potential compromise.
At this juncture the Marco Polo Bridge Incident happened. I do not believe that the Chinese provoked the fight. I think the conflict started with a minor skirmish.
Historical evidence supports Hirohito's claim that he called for compromise with Chiang Kai-shek. Throughout July to August 1937, Hirohito consistently pleaded for de-escalation with the civilian government of Prime Minister Konoe and army high command.
The Emperor took a stronger stance after fighting broke out in Shanghai in mid-August 1937. He favoured a stick-and-carrot approach that would bring China to the negotiating table:
I always told [the supreme command] that we must be menacing [i.e., prepared to use force] and at the same time [be] ready to offer peace terms.
Still, Hirohito's fundamental concern was that the war would be brought to a quick end. In June 1938, he bitterly critiqued the divide between the civilian government, which wanted to negotiate, and the army command, which wanted a further push towards the new Chinese capital of Wuhan:
While one side says it wants to end the war, the other side says it will go all the way to Hankou. It is very deplorable that there is no coordination.
However, much like other Japanese leaders, Hirohito never understood the rising tide of Chinese nationalism and the country's determination to expel the Japanese from Manchuria. In their negotiating efforts, Japanese diplomats consistently claimed Manchuria as a vital part of Japan's security system and refused to come to any agreement that ceded control of the territory. This effectively led to the failure of all negotiating efforts and a continuation of the war.
Source:
Kawamura, Noriko. Emperor Hirohito and the Pacific War. Washington, D.C.: University of Washington Press, 2016.