This is very unlikely but perhaps some Korean pirates could take over and Install the Ainu as a ruling class to keep the Japanese down and a somewhat dominant korean/ainu culture could dominate Hokkaido. Its definitely a reach though
We’re probably getting a Japanese Daimyo, to be honest, but I gotta love seeing ATL Koreans doing some of the only four or five things our ethnic group can do well—study, shoot people, sail, and drink our asses off lmao. You know, cause they’re pirates.
and because pirates are toxic assholes, this is probably how they’d react to a joint Roman-Japanese delegation telling them to politely GTFO:
“Neh, Ilbon hindungi? Yogiseo mo haeyo? Yah, jugulae? Jinjja bahbo ya. Sul jom jusaeyo.”
(Hey, white Japanese guys, what are you doing here? You wanna die? You’re fucking idiots. Get me my booze.)
“I have no idea what this means but you guys are squatting on Imperial soil.”
“The Emperor in Fuyuki or wherever those Westaboo fucks stuck the capital can eat yeot, Pirate Joseon is BEST JOSEON*! You think you can just swamp us in numbers?Our ships are literally crewed by more Kims than you have Tagma soldiers in a 2000-mile radius of here. AND THEY’RE ALL DOCTORS AND LAWYERS TOO!”
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But really, crack aside, stop me if you’ve heard this one before:
-A once sophisticated and powerful empire (Macedonian Rome, Nara Period Japan) is beset by warlords on every side.
-One of these warlords, from a far flung region rich with foreign contacts (Nicaea and Shimazu) topples the decadent or self-destructive regime.
-This warlord and his descendants turn their newly strengthened realm into a bright bastion of Orthodox Christianity on the eastern fringe of their cultural continuity (Rome is one ass-end of Western Christendom whilst Mexico is the other; Japan is the easternmost polity of the greater Sinosphere)
B444 has very clearly set up Japan as the Oriental counterpart to Rome. And, he’s setting up the Triunes as the most powerful enemy of Rome in the long run. Probably.
Therefore, it only really makes sense for Korea to make money moves on the open seas if we end up becoming East Asia’s Triunes. I have no fucking idea what to call it (Empire of Greater Balhae?Daeasadal? Gojoseon Deux: Gochu Boogaloo?) What would this look like?
-Koreans are probably taking the role of the English, seeing as it’s our scoundrels ripping Hokkaido away from Japan and into our bosoms. We’ve also probably got the largest naval assets of the main ethnic groups I’d want to see in this federation. As a result, Koreans wouldn’t really feel much of an attachment to the rest of mainland Asia, with most trade and exploration ties going SE and S of the peninsula.
-Manchus or a similar Tungusic people who ITTL
must view themselves as either Mohe or the direct ethnic and spiritual successors of the Mohe, are the French. The bolded part is critical, as the Jurchen OTL called themselves Balhae’s successors, and viewing a unification with Korea as the return of that multiethnic state is the only chance of this federation working. Not all of them will be living in their eponymous polity, as China and [X] Khaganate will have bits and pieces. They’ll probably provide the bulk of the terrestrial manpower. These NeoMohe will also be the most deeply connected with the rest of mainland Asia. Expect a resurgence or genesis of Tungusic high culture and literature, which would probably be built here from scratch but would also be really cool to see.
-Ainu are, of course the Irish. Yes, that’s right. Ainu townies fresh out of Canalave or Pastoria Cities are gonna wreck your shit if they get even a whiff of Yankees-or-Lakers-equivalent fan gear coming off of you. There might need to be a bit of digging done in order to construct an Ulster Cycle-like epic for Hokkaido, though. Sitonai day parade?
-This federation must be Catholic or Protestant. It will by no means be Orthodox—the Koreans and Ainu will not jump or even crawl at the chance to share a majority religion with the Japanese. Ever heard of a Shinto ajumma? Catholic Koreans will help complete the Triune analogy better as well. The only mainland East Asian populations I see going Orthodox will be former and current steppe tribes. Siberian people as well perhaps.
-Korean will need to become an important commercial language. Not sure how. It’s not like the mineable resources on the peninsula right now are of much use in the 1600s. There’s a SHITLOAD of wood though, and plenty of Manchu coal. Neo-Balhae will succeed well should they choose to hop into the IndRev One bandwagon. If the Triunes do well during IndRev 2, the “you stupid child go be [insert white collar in lab/practice/office]” section of Korean society should help this chimera keep afloat as well, given how shit like Uranium is pretty abundant up nork.
-side effects include total extinction of Korean tiger populations, massive price hikes for ginseng as it can no longer grow in peace in the DMZ, Kaesong being used for non-industrial things with more northern cities taking that brunt, greater strides in (silk hemp or cotton) ballistic armor since more guns mean cheapass rulers get to skimp on metal armor even more than in OTL, etc.
*bonus points for Korean!Hokkaido probably being the northernmost territory ruled by Koreans