Even if answers were given more than one month ago, I might bring back to life this topic to offer another point of view on one of the questions raised behind.

Working myself on 17th century Chosŏn, I read some time ago quite intensely Palais’ “Confucian Statecraft”. He dealt indeed very precisely with 17th military institutions’ reform, but I do not remember anything about a training unit for the explicit usage of the navy. However, training units did exist, for instance the Hullyŏn togam 訓練都監 which trained soldiers using firearms. Navy gunners were mentionned above, they have to be trained somehow because you can not fire a cannon without previous training, and I guess it was in the Hullyŏn togam.

As for the question about outlaws’ recrutment, we do know the importance of piracy in the region, and we do know also that Chosŏn navy recruted at several occasions former pirates to strenghten their troops, or just to reduce the piracy groups. This was done at least at two occasions, under Sejong and once in the mid-15th century. I guess this was often repeated, I think in particular of the Imjin war, but I am not sure and someone else might confirm. Of course, this lead to other questions such as how to integrate pirates, especially the ones who were not Japanese or Chinese, into a national army. But this is another story.

If you still look for more precise information, Eugene Park’s “Between Dreams and Reality: The Military Examination in Late Choson Korea , 1600-1894 (Cambridge: Harvard University Asia Center, 2007) might be the solution, if you did not yet look at it.

The most thorough Choson institutional history in English would be Palais’ second book, Confucian Statecraft and Korean Institutions. The book itself has some problems because the author is split between treating this work as intellectual or institutional history. Rather often, the book conflates the author’s own perspectives with the arguments of Yu Hyongwon, the purported target of analysis, and some of the later chapters completely leave out Yu Hyongwon from the picture altogether. But Palais is extremely erudite, that is undeniable, and offers some exceptional insights. He devotes a whole section to the Choson military system. His arguments need to be taken with some caution but the book is still definitely worth reading.

If the Korean navy did something like that, I’d expect Korea’s marxist historians — and even in the South there’s a tradition of marxist social analysis in Korean historiography — to have noted it pretty clearly.