At the close of Japan's Warring States period, Toyotomi Hideyoshi launched an invasion of Korea, but it failed after the Ming dynasty and the Joseon armies defeated them.
Could this invasion have succeeded-and if so, could it have been expanded to Ming China? How would this have changed the nature of Japan during the Tokugawa period?
This specific topic has
come up four times within the last five months, along with a marginally related
one, and I've put all but one of them on the
wiki, due to the fact that the most recent one did not generate substantial discussion. The answer has been consistent: Japan might hold Korea for around 5-10 years in an extremely optimal scenario, but no more than that, mostly due to logistics. In addition, a "successful" invasion would essentially devastate China, Japan, and Korea to a far greater extent than had occurred IOTL.
I've been of the opinion that Japan had the military power to conquer Korea during this time, but there are considerable issues that make it unlikely. So if you're going to ask if Hideyoshi could have conquered Korea, I would say no. Hideyoshi didn't have a realistic assessment of China or Korea, his total goals were too high, and he couldn't get his generals to tell him the truth about the quagmire Japan was getting into.
Basically, yes. I've explained this before in various threads numerous times.
If you're talking about a POD in 1592 or later, I would say the answer is no. If you come up with a POD earlier, maybe immediately after Hideyoshi seizes power over Oda Nobunaga's former domain, then it might be a bit more possible.
I have three suggestions which Hideyoshi can do: Japan gets a better navy, preferably if the main Korean naval commanders also die conveniently before Hideyoshi invades. Also, Hideyoshi only conquers Korea if he limits himself to Korea, otherwise, the Chinese will strike back if invaded. And he should have a unified command where Hideyoshi's top generals actually cooperate with each other.
Other possible helpful circumstances: if the Wanli Emperor isn't in power, there's less Chinese desire to intervene in Korea. This is strengthened even more if there are more serious issues to deal with. Historically the Wanli Emperor couldn't immediately support Korea because there was a Mongol revolt in northern China. But if they faced a more serious threat, maybe they don't intervene at all. I'm of the opinion that Japan could conquer Korea (but permanently?) though it's not likely because of how Hideyoshi was as a person.
I'll quote the reasons outlining why Hideyoshi wanted to invade Korea:
1) Weaken the influence of the influential daimyo by realizing his ambitions and portraying himself as a hero.
2) Vent his frustrations over the early death of Tsurumatsu, his first son.
3) Secure control over major maritime trade routes.
4) Influenced by Oda Nobugana's prior aspirations to expand into Mainland Asia.
5) Desire to rule "everything under heaven," which theoretically included Japan, Korea, China, India, and Southeast Asia. His hubris was to the point where even after his troops suffered numerous defeats in the first invasion, he demanded a Ming princess as his consort, along with control over half of Korea's eight provinces.
6) He had no direct justification to rule, unlike the emperor, and it was becoming extremely difficult to administrate the archipelago by acting as the regent, as numerous regions retained a certain degree of autonomy. As a result, an overseas invasion was viewed as a reasonable method of indirectly consolidating political influence within the country.
7) Redirect internal tensions by focusing on external issues.
In addition, Yi Sun-shin was far from the only capable military commander, as various other competent ones served under him throughout the war, along with some operating somewhat independently, not to mention that when Won Gyun briefly replaced Yi, he was forced to implement flawed strategies under the government's orders that he had personally opposed. In other words, around 10-20 potential admirals would all have to be killed off to just render the navy less efficient, and probably not even then, as other capable generals could choose join the navy, and implement similar strategies on a naval level based on previous military experience, similar to what Yi Sun-shin had done.
I'm not sure how likely it would have been for the Mongols to launch a significant expedition that would have completely tied the Ming down, given that the Tumu Crisis had been the last major threat from the north before the Manchus (Qing), and it's worth noting that the Ming only sent around 50,000 troops in both Japanese invasions, which comprised a very small fraction of the total force. It also would have made no sense for Japan to just focus on invading Korea (the original objective was to
pass through Korea "peacefully" in order to
attack China, which was curtly refused by Joseon due to remaining as a loyal tributary to the Ming), because it would have been more reasonable to just expand trade routes, which would have led to more gains and much less losses on an economic level. In addition, given that Hideyoshi invaded Korea precisely in order to boost his ego, as he had originated from a low social status, forcing him to look for more radical ways to consolidate his influence, a unifier with a different past would not have taken the same path.
He wanted to conquer Korea, China, and India. Definitely. He planned to move to Ningbo after his conquest, and install the Japanese Emperor in Beijing. That's the type of megalomania that gets in the way of feasible military objectives.
He also wanted to conquer Southeast Asia, suggesting that he essentially wanted to carry out an impossible unification of "all under heaven." As Japan could only have conquered Korea if the process took less than a year, Hideyoshi would have been confident enough to invade China as well, which would have almost certainly resulted in a counter-invasion of the archipelago. Assuming that changes will occur after Hideyoshi's unification of Japan, it would have been impossible for any of the three countries to benefit in any manner.