84 EARLY CHOSON DYNASTYforces, the Japanese found themselves hard pressed when Hideyoshi died on Sep-
tember 18, 1598. Chinese and Korean forces continued their assault on Japan-
ese positions, and Admiral Yi Sunsin was killed at the battle of Noryang on
December 16-I7, 1598. One week later, Japanese troops left Korea, and the
invasion was brought to an end.6s
Forts: Firming Walls and Clearing FieldsOne of the tactical problems of Korean defense was the Korean military cus-
tom of relying on the mountain fort (sansong) for defense. When Hideyoshi
renewed his attack in 1597, the Koreans used the tactic of "firming up the walls
and clearing the countryside," which meant that the peasants were ordered to
take their whole families, their belongings, and their stored grain with them into
the nearest mountain fort. Any who failed to evacuate the villages was subject
to arrest and execution on the grounds that they would automatically be sus-
pected of collaboration with the Japanese, but in practice the forts were so far
away that they usually buried everything in the nearby hills and waited in their
villages for the Japanese to arrive.^69
The main purpose of the tactic was to deprive the advancing Japanese army
of Korean grain even though it forced much hardship on the Korean peasantry.7^0
Ming commanders, however, criticized the disrepair of the walled forts in the
Korean hills and urged their reconstruction, especially the forts at the crucial
mountain passes at Bird's Peak (Seje or Choryong) and Bamboo Peak
(Chungnyong) where a few well-armed men should have been able to block the
advance of thousands. Unfortunately, these passes were not well defended in
the first two years of the war, and they did not playa crucial role in the fighting
at the end.^71 After the war was over the Koreans did improve the mountain for-
tifications, but fate played a cruel trick by changing the nature of the tactics that
would be necessary in the next struggle against the Manchus.
Discrepancies in Gunpowder and Firearms
When the armies of Hideyoshi arrived on Korean shores in 1592, they were armed
with Western smooth-bore muskets, superior to anything the Korean forces had
at the time. Koreans had first used firearms in defending an attack by 500 Wak6
ships after Ch'oe Muson had learned the methods of manufacture from a Chi-
nese artisan. The court then ordered the Firearms Directorate (Hwat'ong-dogarn)
to take charge of manufactureY
Sometime before 1578, the Korean military official, Kim Chi, had cast a new
type of small-arms weapon, the sung-type gun, a piece that averaged about 55
centimeters in length with a bore 2.5 centimeters in diameter. This proved to be
no match for the Western musket or fowling piece, however. The Korean gov-
ernment learned that the Japanese possessed the Western-style musket when a
Japanese envoy, S6 Yoshitoshi, brought one as a gift in 1589, but the Koreans