Thank you for suggesting this scenario. I'll look into it. I was thinking about how the Later Yan could stand up better against the Northern Wei before Goguryeo started expanding into North China, and this seems like a great possibility.
Hmm, a point of divergence that early could let the Later Yan win the Battle of Canhe Slope, and also leave Murong Chui alive. What about the idea of Later Yan being more of a threat to the Northern Wei? Instead of Tuoba Gui (Emperor Daowu) establishing the Northern Wei, there could be a few weak states in North China instead. Later Qin could exist in this scenario too.
I'm not sure what you're asking. During the Three Kingdoms Period, there were essentially three China's, with three different dynasties claiming to be the rightful one.
If you're looking for a permanent division of China, this probably isn't the best time period either. Out of the three dynasties during this time, one of them had about 2/3 of China's population, which paves the way for eventual reunification.
But with all that population, they didn't do much with it for a good while. There was nearly half a century of official division. How long does it take for an "independent from the other guys" mentality to take hold?
Maybe three China's in the long run is asking a bit much, considering Shu Han's politics and resources. But would it not be possible for the Cao and Sima clans to come to blows in a civil war in the north, holding them back, and allowing a greater longevity for the other two kingdoms to build up more?
....What did I do to kill this thread?
So how could we keep the Sui dynasty from ending as abruptly as it did?
Well, that's kind of hard, as Sui was hellbent on making a name for themselves, and weren't afraid of drowning themselves in an ocean of blood to do s. Also, they got their asses kicked by Goguryeo three times in three years.
Well, conflict between Sui China and Koguryo is inevitable, but it doesn't have to end in Chinese defeat. By the time you get Emperor Yang of Sui, I agree it will be very difficult for the Sui to continue, with such a terrible ruler at such an early point in the dynasty's history, but by going a bit earlier with Emperor Wen, things become more positive. While Chinese success in the 612 invasion might be possible, changing the outcome of the 613 and 614 invasions doesn't seem too likely. I'd suggest that if Emperor Wen's invasion of Koguryo in 598 does better, the Sui might survive in the long run. This defeat can be blamed partially due to weather, whereas the others can't be.
I don't know about 598, Goguryeo may have lost the Han River valley that made it force to be reckoned with to Silla, but they probably could've beat Sui anyways regardless of the weather, given the quality of their army.
Wait, why? 598 is just a few years after the Sui conquest of Southern China. The Sui army and navy are still experienced from their campaigns in Southern China, and Sui forces would have success soon after against the Turks. It's not like Koguryo is invulnerable, and I highly doubt that Koguryo's lack of success against Silla is because Silla had an army of even higher quality than Koguryo.
Well, conflict between Sui China and Koguryo is inevitable, but it doesn't have to end in Chinese defeat. By the time you get Emperor Yang of Sui, I agree it will be very difficult for the Sui to continue, with such a terrible ruler at such an early point in the dynasty's history, but by going a bit earlier with Emperor Wen, things become more positive. While Chinese success in the 612 invasion might be possible, changing the outcome of the 613 and 614 invasions doesn't seem too likely. I'd suggest that if Emperor Wen's invasion of Koguryo in 598 does better, the Sui might survive in the long run. This defeat can be blamed partially due to weather, whereas the others can't be.
Emperors Wendi of Sui and Taizong of Tang had never lost a campaign until they invaded Goguryeo. In both cases, they were able to take several Goguryeo border fortresses, but failed to advance any further. Had Goguryeo been defeated earlier than in OTL, either the Sui or the Tang would have had to face a probable Baekje-Silla alliance, which would have been hard to conquer based on how Silla repulsed the Tang in OTL.
This is oversimplification as well. There's a very good reason why Goguryeo held out against the Sui and Tang for 70 years and six expeditions. Although there was a 30-year break in between, 40 years is still a long time for a state to resist another that was about 10 times its population. All eligible males in Goguryeo were trained to fight in case of a war, so there was no problem with conscription. Goguryeo also either allied with or maintained tributary relations (usually in Goguryeo's favor) with Khitan and Mohe tribes, and also allied with the Turks, urging them to revolt against the Tang so that Goguryeo would have breathing space. In other words, you would need to make sure that Goguryeo would be isolated from its allies, then break through two lines of fortresses to successfully invade Pyongyang, and finally subdue the southern kingdoms. By the time that someone accomplishes or attempts to accomplish this, it's very likely that there would be border issues with bordering states to the north or west, or an uprising protesting against such a long and exhausting campaign or campaigns.
The main reasons for Goguryeo's fall were political strife among the three sons who succeeded the Prime Minister, including one defecting to the Tang and fighting for them, and Silla allying with the Tang so that both states could converge on Pyongyang. As a sidenote, Balhae, which claimed to be the successor to Goguryeo, was established 30 years around the same area after Goguryeo's fall, and eventually ended up outlasting the Tang. During the transition between states, the Tang never held effective control over Goguryeo's former territories for long.
While it's easy to blame the constant Sui-everybody wars for the downfall of the dynasty, some of these were actually necessary. For example, if the Sui is going to survive, it needs to have success against the Turks to the north and Koguryo to the northeast. The war against Champa, on the other hand, is not so necessary. The other major cause of the Sui downfall, massive conscription for public works projects, can be ameliorated if the government sticks only to the Grand Canal and other required infrastructure projects. While moving the imperial capital from Chang'an to Luoyang might have been helpful and even valuable, it wasn't required, as centuries of Tang rule from Chang'an show.
Overall, I lay the blame for the Sui Dynasty's defeats on the reign of Emperor Yang. I assume one of Emperor Wen's other sons could have done a better job maintaining the dynasty, because things probably can't get any worse than they did historically.
I will also add that the main reason for the first war was due to Sui officials discovering Goguryeo diplomats in a Turk camp, which implied that Goguryeo was ignoring Sui's requests for submission. Although the first campaign failed in part due to adverse weather conditions, all of the other campaigns also had to be abandoned as winter set in, and the Sui forces were defeated both on land and sea, which meant that Goguryeo was thoroughly prepared. Later, during the second campaign, Goguryeo's main strategy under Eulji Mundeok during the conflict with the Sui was to lure the enemy further into Goguryeo territory, then devastate them in a decisive battle, which is what occurred in the Battle of Salsu River. Ultimately, Goguryeo's determination to remain independent, and the Sui's failure to effectively supply its troops, inability of the generals to make independent decisions, and low morale caused the campaigns to fail.
I'm not really sure about what you mean when you state how the Sui needed to attack the Turks and Goguryeo to survive. Goguryeo was more concerned about maintaining a general balance of power between the states in the area, which was why it made a preemptive attack in Shanhai Pass around 595 in order to assert its dominance over its respective region. It also sent diplomats to the Turks because it was preparing for a Sui invasion, and neither Goguryeo nor the Turks probably thought about attacking China.
If another Sui successor decided to attack Goguryeo by utilizing more effective strategies, it would still have been hard for him to be more successful than Taizong of Tang, who was initially successful because the Goguryeo generals who initially clashed with him on his way to Ansi Fortress failed to comprehend the Tang's strategy. However, he failed to realize that there were numerous Khitan and Mohe tribes, which meant that although some sided with him, the others had been allied with Goguryeo for decades and did not have a reason to aid the Tang. In addition, his deliberations before approaching Ansi and his failure to take it illustrates how although he might have taken more fortresses if he had utilized a different strategy, he would eventually have been bogged down after losing contact with supplies or guerilla warfare deep in Goguryeo territory.
As a result, although it's unlikely, if the Sui had acknowledged Goguryeo dominance in Northeastern Asia, both states might have lasted for at least several decades or centuries longer than in OTL.
Well, I'm not really talking about a Sui conquest of all Koguryo. I certainly don't think the Sui were ready to do so in 598, though I was envisioning that a victory in that campaign by Emperor Wen would satisfy the Sui for a few decades, avoiding the need for conquest, and the Sui could expand its territories in a few decades, after the completion of the wars with the Turks or the building of the Grand Canal. I was more focused on Sui reconquest of former Han Dynasty territories, though functionally, that's most of Koguryo's territory. I think Sui dominance over those territories is possible in this scenario: a few decades after the Sui have become established as a Chinese dynasty, Koguryo can't necessarily count on rebellions in China distracting the Sui, and I'm rather surprised that Sui China didn't try to strike any deals with Silla, Baekje, or even Yamato during its invasion of Koguryo.
And wars with Koguryo and the Turks will be necessary. Koguryo because it launched the attack first on Sui territory, and the Turks because they have that bad habit of invading China. For the Sui and Tang, Northeast Asia is a border that needs to be secured.
By the way, wasn't one of the problems with the Sui invasion that they didn't break the fortress lines? I'm pretty sure they were harried the entire way to Pyongyang by the fact that they didn't get those fortresses, and chose a sea route while at it. That's one of the reasons why the Sui lost too: they never really occupied the land they conquered, leading to the supply issues.
Although you mentioned it, a Sui victory over Goguryeo would essentially entail conquering most of Goguryeo, and the territory that would be left over would only be Buyeo/Mohe territory, which was not heavily defended to begin with. Taking what had once been part of the Han commanderies would also include Pyongyang, which was also Goguryeo's capital, so the country would have collapsed if the Sui had succeeded. Even though the Sui would probably have utilized its full capacity, Goguryeo would still have been adequately prepared, and if they felt that the tide was turning against them, they could have called on the Turks for assistance, as it did during the conflicts with the Tang. I personally don't think that any Chinese dynasty would have tried to send a diplomat to any of the states you mentioned because both the Sui and the Tang felt that the campaigns could have been concluded within half a year or so, and never intended on planning for the long term. In OTL, Silla was the first to send an envoy to the Tang after Yeon Gaesomun had rebuffed Kim Chunchu's request of an alliance against Baekje because Goguryeo demanded the return of Silla's northern provinces.
Again, as I said earlier, it's more likely that Goguryeo attacked first because the Sui demanded submission, and not because of issues such as territorial disputes. In fact, Goguryeo gave up the buffer region in Liaoxi before the second war with the Sui because the corridor was too narrow for stationing the troops. I'm not sure how the Sui could have resolved its issues with the Turks, but if both sides had come to a more thorough diplomatic agreement, then a more stable peace might have been attained.
Well, that was my point. Eulji Mundeok made sure that the Sui were drawn into a trap by abandoning certain fortresses and ambushing the enemy at certain choke points. That was why even though the Sui were able to reach Salsu River, which is in what is now North Korea, the fact that they were constantly harassed and were low in morale caused their defeat and withdrawal.
For those who skipped the wall of text, the what-if was "What if China, Paekche, and Japan fought Koguryo and Silla?"
Japan fighting with China is somewhat unlikely, since they had a rather cordial relationship with Goguryeo, and if even bother getting into this conflict at all, it will be on Goguryeo's side.
Baekje on the other hand might fall on either side if get's them their precious (and valuable) Han Valley back. But as history shows, Baekje has reasons to be pissy at both Silla and Goguryeo that might prevent them allying with either (which was something that doomed them OTL)
As for Goguryeo and Silla fighting on the same side in your time frame? That's just insane, it would be like France and Germany fighting on the same side in WWI with a POD of 1904.
I was asking, with a point of divergence in 598, whether there could be a Koguryo-Silla alliance by sometime between 640s or 650s. If you altered 1904, you could probably pull off a Franco-German alliance by alt-1950. It would probably require Paekche pulling off major reforms (and maybe allying with China), but that's the whole part of a challenge. And weren't Paekche and Koguryo allied? I'm pretty sure they were. And at the same time, I'm pretty sure Japan's participation was due to a fear of Silla and Tang, not because of its relations with Koguryo, since I'm sure relations with Paekche were much closer.
Japan's participation seems pretty arbitrary: I've seen a lot of claims about the Yamato-Paekche connection, but many are somewhat lacking. I'm thinking, if China managed to ally with Paekche (though Paekche was in my opinion the weakest of the three), it would be the most likely to bring Japan in.