In this world, the Song Dynasty was able to begin the process of industrialization. Chinese Kongsi began to take on real power, taking into their hands the destinies of other nations and guiding them on the path to prosperity -- or so it comforted many scholars to think of it as they gave thanks that they were scholars and not Scottish factory workers, men and not women, Chinese and not barbarians [1]. Following trade came the empire, bringing order out of chaos, and ordering the world, protecting the sacred across every land (the ones who acknowledged his Celestial Magnificence that is). Not only the kings of Korea and the Vietnamese, but also the kings of Japan, Corboda, Rome, Tenochtitlan, and more than most could name. Chinese steamboats prevailed from the Nile to the North Sea yet did not grow stagnant for the struggle between the trading companies abroad was vicious, so they might establish a monopoly in an area and profit when the bureaucrats came behind to bring it well-ordered government. In this way, the European Peninsula was largely unified under the beneficent rule of the Luoyang-advised Holy Western Kings [Frankish Emperors] and the British Isles brought under the similarly well-guided Scotts.
Yet even as these long-divided realms united, the Imperial Realm, so long united, was dividing. The ruling of Tenochtitlan proved lucrative and attracted many immigrants, who increasingly began to spread to the North and the South. Unfortunately, this process was allowed to continue until those provinces became strong enough to exert significant pressure on the Dynasty. Eventually, conciliation failed and war broke out. The war raged, in phases and combinations, for forty years. When it was over, most of the Kongsi had been forcibly disbanded and liquidated, and the possessions of the Far Eastern Rebels were liberated from their control. The Dynasty was only narrowly saved from total collapse, and many overseas or far-inland provinces had to be trusted to govern themselves with only a tributary ambassador to tie them to China for the foreseeable future [2]. In this climate, the fall of the Holy Western King's Younger Brother to the radicalism that had overtaken so former tributaries, including the vast Srivijaya Complex [3] and
its Younger Brother the Pandya [4], could only be greeted with alarm, even if he (like the Caliph in Corboda) no longer remembered to send proper tributaries.
When this new rebellion made war on both the King and the Khan of the Golden Horde (whose fathers had diligently paid tribute to China going back to before industrialization), war was inevitable. The Polish Commune was able to achieve alarming successes but the overwhelming weight of the coalition against it was able to begin to drive it back. But then, in a great catastrophe, the Poles were able to detonate a nuclear weapon, forcing an end to the conflict. Neither side was willing to surrender for reasons of foundational principles, but a war between nuclear powers was too risky to be contemplated. Reluctantly, the standing borders on the ground were surrounded by demilitarized zones, as both sides sat back and waited. Now soldiers from every part of the world gather their, patrolling those grim walls, waiting to see if tomorrow brings the end of the world, as they march all along the frontier.
[1] IIRC this is a paraphrase of something written by an OTL Song scholar. Without the Scottland part obviously.
[2] Many of these ambassadors failed to show proper deference when they arrived or got waylaid or were never appointed. Such are the dismal times.
[3] Mega-Indonesia, including Australia, New Zealand, and Papua New Guinea
[4] Successors to the Chola, from whom the Song had so considerately returned Srivijaya's domains
