The Empire of Japan is one of the three primary Axis Powers alongside Nazi Germany & Fascist Italy which fought against the Allies. Yet Japan's transformation into far-right authoritarianism contrasted with its co-Axis partners.
The rise of fascist dictatorships Italy & then Germany was pretty clear-cut: fascist parties rose to power under a single supreme leader in midst of political, economic & social chaos; and both sought expansionism which then caused WW2. This seemingly does not occur exactly the same way in Japan in which there was no fascist party or a 'Hitler'/'Mussolini' figure.
Rather, as far as I'm aware, the military grew in power and influence as such that it trumped & eventually took over the civilian government without a coup. This then also corresponded with the prominence other extreme ideologies like ultranationalism, State Shintoism, Showa Statism ("Japanese fascism"), and pro-expansionism in Asia, whether to 'liberate' Asia from West or/and 'unify' it under Japanese rule.
While I have a rough idea of what happened, I am struggling to gain a clear understanding as to how and why the situation in Japan during the Interwar and WW2 years occurred.
Why did militarism - and other associated ideologies: ultra-nationalism, expansionism, State Shintoism and Showa Statism - gain traction in Japan that it eliminated the "Taisho Democracy"? Did these reasons go back as far to the Meiji Restoration?
Why did 'process' start in the 1930s? Namely with the Manchurian Incident (1931) despite some of the factors - independence of military and nationalism - already existing decades before.
Why, despite mulitple failed military coups in the early 1930s, did Japan eventually succumbed to a semi-fascist military dictatorship, seemingly by the civilian government under civilian Prime Minister Prince/Duke Konoe Fumimaro?
There's a lot to unpack here. If you're really interested in learning more about this topic, I can wholeheartedly recommend Hirohito's War by Francis Pike, he digs into a lot of the details that I'm getting ready to go over, but does so in a way that's relatively easy to understand. I could also mention Hirohito and the Making of Modern Japan by Herbert P. Bix as it goes into a lot of detail about how Japan descended into ultramilitarism.
It goes like this. Japan after the First World War was embittered. Like Italy, it felt that it hadn't been given a fair deal at the Paris peace deal and, as a result, was embittered at what it saw as an Anglo-American alliance concerned with tying it down. Those fears were exacerbated by both the Washington and London naval conferences, which again convinced the Japanese that Westerners were primarily concerned with repressing Japan's attempts to expand by limiting the size of their fleet.
Militarism itself was already engrained in the Meiji and Taisho eras, but was not given an outlet because of the ability of the Emperor and the genrō (men such as Saionji Kinmochi who had helped establish the Meiji state) to control them. That changed during the Taisho era.
I feel that Taisho democracy is somewhat of a misnomer. While Japan was ostensibly democratizing during this era, it was a far cry from the Western demoracies of the time. A small eligible electorate and inimical political parties who suffered from near constant infighting undermined whatever electoral process existed. The near absolute authority granted (in theory, but not always) to the monarch plus the extra-constitutional role of the genrō (who selected the Prime Minister for approval by the Emperor) meant that democracy never fully took root in Taisho Japan. So, you could say it did, indeed, go back to the Meiji Restoration.
Another problem was that, in the 1930s, the Army and Navy cabinet ministers were again allowed to be pulled from the active role lists. This allowed both the Army and the Navy to veto government policy that they found unfavorable or a prime minister that they did not like by resigning or refusing to form a cabinet. After all the other genrō had died and an aging Saionji was the only one left, this effectively gave the military a veto on government policy. This, in turn, led to the ascension of Konoe Fumimaro, who was seen as a figure pleasing to the military.
So, the roots of military were in place way before the Manchurian Incident (1931). That incident, in which middle officers like Ishiwara Kanji seized the initiative, was approved post facto by Hirohito. When the same thing occurred in 1937 at the Marco Polo Bridge in North China, Hirohito again sanctioned the move, believing himself simultaneously to have no choice and also because he felt it was advantageous to Japan's position in the world.
The road to effective dictatorship is covered really well in The Last Banzai by Courtney Browne. I'll be brief. By 1941, after Konoe failed to prosecute the Second Sino-Japanese War in an effective way, the path was cleared for Tojo Hideki, an effective administrator who ran the secret military police in Manchuria, to take over. Tojo gradually assumed dictatorial powers, helped by laws passed under Konoe that limited dissent, and eventually assumed for himself several ministerships and the Prime Ministership. Despite this, Tojo was no Hitler or Mussolini from a control perspective, and battled with the Army and Navy to draft effective policy. This limited his effectiveness as a "dictator."
I hope this answers your question. Blessings!