At any rate, the reach and power of the central government is best realized by looking at the extraordinary control the Shogunate had over the lives of common people. The government was able not just to do common things like assess property and levy taxes, but also to force families to form lasting, quite unpopular mandatory ties to a Buddhist temple, to force them into an extremely strict occupationーbased caste system, etc.
Building upon
this shitty webpage(because it confirms what I recall reading in a working paper on a comparative analysis between Edo and Joseon taxation a few months ago and I can't find it right now):
as the webpage indicates, taxation was collected by local authorities who in turn gave them to the shogunal authority; does not seem to be the direct control that what you stated seem to imply. Also note that the Boshin War was ultimately between two factions of Japanese domains, which would've never been the case for Joseon or the Qing - Tonghak/Boxers had no institutional assistance,(surrounding Chinese armies not assisting the effort was ultimately because of the Manchu-Han schism within the bureaucracy) and Xinhai only succeeded because Yuan's New Army supported it - the warlordism that arose from it was also relatively new, nothing like what Edo-Meiji Japan was OTL.
I should also mention that samurais - the social class and identity that must be most known about pre-modern Japan - ultimately did not declare loyalty to the country, but to their individual lords. There exists no Korean or Chinese equivalent, either military or civil, where loyalty ultimately lies with regional authorities and not with the central government.
Of course you are correct that modern nationalism did not exist in Japan in 1860, but then, neither was it yet universally accepted in the US at this date, as evidenced by the popularity of "My country is Virginia, sir"ーism.
I can't comment on this as I've never heard of it, but it does seem to indicate part of the many reasons why the US may have been in civil war OTL.
At any rate, modern nationlism of this sort did not appear in China until May 1919, and it was noticeably absent during the SinoーJapanese War of 1894ー1895, as evidenced by the refusal of local armies in provinces not under attack to send troops to the battlefield, the failure of the Southern Fleet to help the Northern, the refusal of the Hui armies at the Battle of Pyongyang (one of the bestーperforming units in that battle) to continue the fight under a nonーHui general after "their" general had died, and so on.
My point on "Japan importing Western nationalism" and China/Korea finding that relatively unnecessary was because unlike Japan, which as mentioned ultimately just came from a tradition of regionalism and feudalism, had experience of living under central governance for centuries; in both countries the central government selected the head for each prefecture or some equivalent.
I remain deeply suspicious of any claims of a unified national identity as we now think of it existing anywhere in East Asia prior to about 1890.
See above. Korea ultimately experienced a unified national identity after the fall of Koryo because Joseon saw further reforms in administration and cut local power from the knees, something that Japan would be able to achieve by 1871.
I think most historians would agree that the reason Japanese leaders were able to push through industrialization and modernization so quickly after taking power, and China and Korea were much less able to do so, is that Japan already had (national identity or no) a relatively powerful centralized government that could overcome, coーopt, or ignore the wishes of conservative cultural elites, opposition nobility, and so forth.
I liberally use your argument above that such conclusions drawn from "cursory popular history books" are not a particularly accurate depiction of history.

Japan was not successful in that it was able to allow its conservative elites agree to a reform due to some centralised bureaucracy, but because the initial shocks of the Perry Expedition and further incidents were so widespread across the country; Korea saw a much limited response(1875 saw a huge response, by which time it was too late), and China's Opium Wars ultimately *did* see a strong response, which was the Beiyang fleet; if it wasn't for Cixi completely gutting the expenditures for modernisation history would've been vastly different. This possibly adds to how significant the leadership ultimately is in successful modernisation.
In both China and Korea, similar efforts at modernization faced much greater challanges from conservative aristocrats, elements of the royal court, etc, and had more trouble pushing past them.
Adding onto what was previously stated, China ultimately suffered from the Manchus rightfully fearing a decline of its capacity and power, while the Han was very unwilling to cooperate(ultimately, modernise) with the former; Korea only saw a unified voice for modernisation by 1884(my POD yay pls visit the Twelve Republics TL) by which time - as said - it may have been too late.
But in 1922, Japan gave up all political and military control over Shandong (retaining only economic rights there).
Ultimately a part of the general retreat in foreign policy, along with retreating from Siberia, due to huge financial losses. Much more a realistic decision than an ideal one to "preserve the Chinese state" or etc.
In 1925, she shocked and angered the UK and US when, in an international meeting to set Chinese tarriff rates, she argued that China should regain the ability to set her own tarriff rates.
Considering how much economic control Japan already had over China, it was already in a position of advantage; furthermore, since the First Sino-Japanese War Japan was wary of "being dragged along" on agreements, particularly on financial matters.
In 1927, when the US and UK wanted to launch a punitive expedition to punish China for the 1927 Nanking Incident, it was Japan who said no, meaning that no punitive expedition was ever launched.
The Chinese wikipage indicates that the foreign minister believed such a punitive expedition would be detrimental, as the situation ultimately was caused by the Communist Party, not the Nationalist government.
To use another nation as an example,
If we are to argue that geopolitics and strategic interests are non-existent, does that not remove the entire point of discussing these matters? German foreign policy OTL during those two wars ultimately came forth from centuries of development of the concept of "Volk ohne Raum" and the practices of "Ostsiedlung", and in an neo-imperialist environment a conservative government in Germany would ultimately pursue a policy that looks similar to OTL, either by becoming hostile towards the west or east - unless there exists such large a threat that necessitates cooperation with its neighbours. Japan, which ultimately did see the strengthening of the Emperor as a centrepiece of nationalist ideology even before 1900 and continued military successes across Asia, would have become more and more expansionist unless another major power was to stop it - China, the United States, and Russia all being possibilities.
Nor do I agree that overseas expansionism was necessary to unify or to keep unified Japanese society.
Adding to what was stated above, considering the fact that Seikanron existed before Meiji Ishin it's even possible to argue that the Second Sino-Japanese and Pacific Wars are all part of expeditionary warfare being used to weaken regionalism since the days of Toyotomi Hideyoshi.
The initial phase of expansionism in 1931 was fairly popular with the general public, but this is not least because of the problems and instability created by the Great Depression, and the widespread image that "at least someone is finally acting decisively".
My conclusion on the matter that it was not so much about the great depression(which Japan
ultimately did not actually come to experience along with the ROW) but more about the growing income inequality in the rural areas due to terribly high rice taxes and the continuation of statist education from the Meiji era.
This did not have to be. It was also helped out by newspapers trying to outーjingo each other in an attempted to increase circulation, but this too did not have to be.
I agree those newspapers had to control themselves, their spinning of the Washington Naval Agreement back in 1922 as some attempt to keep Japanese power in check ultimately contributed a lot to the growth of ultranationalism.
I suppose a foreign war will always have some sort of rallyーroundーtheーflag effect, but let us not forget that earlier Shidehara diplomacy, which is, if anything, antiーexpansionist, had a very real base of support within large chunks of the Japanese ruling elite, from business leaders, to Privy Council members, to members of the Imperial Family, to even military men (especially older Admirals). In OTL, this faction proved weaker, or at least did not win out in the end, but that fact that it existed at all, and was as strong as it was, shows that the victory of an expansionist ideology was far from inevitable.
And Taaki, who ultimately came to point Shidehara as foreign minister, also enacted the Peace Preservation Law, did nothing to aid the Koreans in the aftermath of the 1923 earthquake, and began to enforce universal military conscription. I can only come to believe that such pacifist foreign policies were paid in blood with the reforms above, due to the large conservative presence in the legislature, bureaucracy and military most likely being unwilling to enact the policies without concessions. Let's also not forget that Hamaguchi - the second PM that appointed Shidehara - was almost assassinated by a far-right activist and ultimately died from the wounds.
In a more peaceful and prosperous Japan, I see no reason that Shidehara diplomacy that seems to be effective in increasing the Japanese standard of living could not also unify the public, if such a thing is needed. After all, from 1945 until 1990, the cornerstone values anchoring virtually all Japanese opinion were pacifism and economic growth...
I think both of us can agree that OTL Chinese foreign threats are taken so seriously because of the massive public support - and this ultimately arises from the nationalist education that the population received. While post-WWII Japan may have been at liberty to enact pacifist education, the Empire of Japan beginning from Meiji most likely needed such nationalist and statist emphasis due to experiences with Boshin and Satsuma - a presence of threat both imagined and real, as was evident with the radicalisation of the Navy/Army.
To sum up your three points and my response:
- Japan wasn't divided compared to China or Korea
Due to China during the time being under foreign occupation, a cursory application of examples can be very flawed. Korea however was under central government from the beginning of Joseon, in both administrative/political/military terms. (China was also very centralised on administrative terms.) Japan was unable to go through the process earlier and therefore, when issues of regionalism became apparent through Boshin and Satsuma, strong nationalist education became necessary.
- Overseas expansionism wasn't "inevitable" for Japan
Assuming regionalism wasn't strong in Japan, expansionism was ultimately inevitable if its neighbouring countries were so weak; the initial successes against China and Russia, mass-printed in woodblocks and distributed across Japan, formed a collective memory of fondness towards invading other countries or "pacifying them", an attitude which became radicalised due to hostility of the West against a rising Japan, the general policy of colonialism that dominated the world at the time, and the 1923 Earthquake.
Assuming regionalism is strong is Japan, expansionism is useful in keeping regionalism at bay through foreign expeditions, as was evident in Seikanron, and the Japanese invasions of Korea in the 16th century.
- Overseas expansionism wasn't necessary to unify or to keep unified Japanese society
Adding on the what was said above, it definitely should be noted that there did exist high-profile Japanese pacifists and/or left-wing politicians, such as Shidehara. But individuals like him, while heroic and audacious in their actions and rhetoric, were ultimately drowned in the growing numbers of far-right politicians and radicalised military officers, loudly supported by a young generation of ultranationlists - an inevitability considering the domestic situation being added to the world at the time being conducive to imperialism and militarism.
My theories are weak and since you're the expert on Japan I hope to be disproven in my theory but as of yet I don't think there's enough evidence or strong argument to be proven otherwise.
Edit: I was struggling to understand why all your dash marks, commas and etc can't be read on my iPad - I gander is that it's because you're using the one for a Japanese-language keyboard. Mystery solved.
