I have recently been researching on Korean history (I'm Korean American) and one person that really stuck out to me was Yi Sun-sin. From the amount of sources that back it up, there is no doubt that he was an amazing naval commander. However I have a few questions about the credibility of these numbers.
I saw in one of his major comebacks, he was able to defeat a Japanese Navy fleet of about 200 ships (or more) with just 13 ships. No matter how great of a commander one may be, I feel like this really pushes the limits and just may have been written to make him look bigger. Did this really happen or more likely exaggerated?
Note that these were ships and not warships. More than half of the Japanese fleet at Myeongnyang were logistical ships - transports and supply ships. Yi estimated in his diary that at least 133 were warships. These numbers certainly weren't exaggerated, the reason why Yi was able to defeat so many Japanese ships was because he used the currents to his advantage. The Japanese ships, closely packed together, ending up crashing into one another when the current changed.
The Joseon Sillok also records that a captured Japanese commander said there were 120 ships on the Japanese side. The numbers don't seem to conflict with one another.
The numbers are in line with what the japanese fielded in other sea battles so there's no real reason to doubt them or see them as exaggerated. For example Yi's fleet numbered 150 prior to WonGyun losing most of the ships.
The plan worked because the battle took place in a narrow strait with a fast & wildly varying current. Every day at a certain time the current literally changes direction. Yi timed the battle so that the japanese were caught in the strait when it changed. So the japanese ships were stuck in a narrow strait with a current that was pushing the lead japanese ships back onto their own fleet, leading to mass chaos and collisions.
Meanwhile Yi's ships were outside the strait (where the japanese ships couldn't reach) just firing volley after volley at the chaotic mass of japanese ships.
The victory wasn't so much due to seamanship as the clever use of terrain.
The warships and tactics used by the different sides were quite different! Korean panokseon ships had flat keels for coastal waters and were heavily armored and loaded with dozens of cannon. By contrast, Japanese vessels were built for open ocean conditions and speed and lightly armed, typically with only one cannon. The primary Japanese tactic was to fire muskets, close rapidly, grapple, and board.
In the lopsided victory at Myeongnyang, Yi Sun-Sin forced the Japanese navy to attack through a fairly narrow strait that crowded them together and kept them from flanking the much smaller Korean fleet. This made them a perfect target for long range cannon fire and destruction from a distance.