I remember reading an interview with Ikuni about how he first encountered the idea of revolution which appears in the show when he was a kid watching the Student Movement protests of the late 60s and early 70s, which were anti-authoritarian in a broad sense (they were leftists and against American imperialism, but also explicitly opposed Japanese nationalism and Stalinism and weren’t aligned with the JCP). This was the same period down to the years when Yukio Mishima’s far-right militia was active (1968-70).
Another early inspiration of his to both art and weirdness was experimental art and theater of that era, which was very much connected with the Anpo protests (and which, not incidentally, includes a company which is still going called the Revolution School), which was also following a wartime tradition wherein Shingeki (Western-style theater) which Angura reacted against, had been appropriated for propagandistic purposes by the military too.
I feel like I MUST bring up Tenjou* Sajiki here too because it was a fixture of the Angura (experimental/underground) movement listed above, and because much of its music was done by none other than J. A. Seazar. Also because:
the group has produced a number of stage works marked by experimentalism, folklore influences, social provocation, grotesque eroticism and the flamboyant fantasy (x)
So it totally makes sense to me that an aesthetic of modernist authoritarianism would represent the “shell” which is broken by a messy, adolescent group of weirdos (affectionate), and that the world-breaking happens to look a little like Ikuhara’s theatrical and artistic radicals (and their own egg shaped things).
EDIT: Wait I found more specifics. Mishima was a literary “rival” of one of the most critical founders of the Angura movement, Shuuji Terayama! Here is more. Warning for a fairly graphic description of Mishima’s committing ritual suicide, though.
Mishima’s contemporary and sometime adversary Shūji Terayama responded to Japan’s cultural crisis of the sixties by arguing that only art could transform the world. The only real revolution, he said, was in the imagination. Mishima disagreed with this view profoundly. To back up his ideas, he formed a private militia—which he called the Shield Society—made up of university students who shared his right-wing values and his vision of a prelapsarian Japan. At the end of his life, Mishima claimed that writing had little value for him: he wanted to leave the world of words for a world of action.
*though it is a homonym the theater’s “tenjou” 天井 and our beloved protagonist’s surname (天上) are not the same barring the fact that they both contain “天” heaven/sky, but the rhyme may or may not be coincidental
ellievsbear
romaincrisis
tangentwithtanner
origamiaround
