If the Sui were in such a poor position to be engaging in what is clearly a massive expensive campaign what were their goals in trying to invade Goguryeo? Conquest of the entire Korean Peninsula? Would they have stopped at Goguryeo or gone on to Bekajae and Silla? Did whatever that existed in Japan factor into any of this?
Wendi's campaign was chiefly motivated by his strategic interest in the Liaodong Peninsula, and his general claims to universal rule modified by the fact that he thought he actually could militarily subjugate Goguryeo, as opposed to the Tujue which were clearly out of the question. Since the invasion was mostly opportunistic, when it failed in 598, Wendi was more than happy to resume normal tributary relations.
Yangdi, on the other hand, seems to have gone all-out for conquest; the Liaodong territories that his armies occupied in 612 were incorporated into the military and civilian governmental infrastructure of China in the midst of the campaign. The initial
casus belli, insofar as there was one, was the discovery of a secret Goguryeo envoy at the camp of the Tujue qan, but this was of course just an excuse. He then went overboard. It's not clear that all of Korea would have been targeted next, but there's no reason to suspect otherwise, since the various claims that Wendi and Yangdi extended over Goguryeo harkened back to Han/Jin control over the entire peninsula. But it's awfully hard to predict what Yangdi would've done.
The Sui did have relations with the empress of the Yamato, Suiko-
tennō (yeah, I'm
that uninventive), but they chiefly revolved around precedence. The Yamato sent several embassies to the Sui, initially to learn more about Buddhism, and Yangdi attempted to employ them as vehicles for spreading glorious Chinese culture. He also seems to have thrown a colossal hissy over Suiko-
tennō's temerity to refer to herself in exalted terms similar to his own. Eventually the Japanese seem to have accepted a position of minor inferiority to the Sui in diplomatic parlance. There is some suggestion that the initial embassy to the Sui was to make sure that they didn't interfere with a Yamato military expedition against Silla (or even enlist Sui support), but there's really nothing to support this except for a late source, the
Nihon shoki; it is nowhere in any of the versions of the
Sui shu.
Karalysia said:
Is there any credence to the Chinese revisionism about Goguryeo as a regional Chinese dynasty?
Eh? I wasn't aware that this was taken seriously by anybody.