78 EARLY CHOSON DYNASTYto about 500,000 men in J 592, with no more than 100,000 men in the northeast
region of the country. On the other hand, military organization had been reor-
ganized successfully according to plans developed by Ch'i Chi-kuang, who fought
against the Wak6 in Fu-chien Province in 1563 and who published his book on
military organization, the Chi-hsiao hsin-shu, in 1567. His text was taken over
as a manual by Korean military officials during the Imjin War. Ch'i divided the
infantry into ll.ve groups: musketeers, swordsmen, bowmen with fire arrows, ordi-
nary bowmen, and spearmen, and he provided that the infantry be accompanied
with cavalry and crew-served artillery units.44 Thus, while the Ming soldiers may
not have been as experienced, battle-hardened, and skillful in the use of mus-
kets and group tactics as the Japanese, they were by no means a pushover, and
the Ming army had greater numbers and direct access by land to reinforcements.
The First Phase of the lmjin War. 1592-93In a letter Hideyoshi sent to Korea before the invasion in 1592 he revealed his
plan to conquer Ming China, install the Japanese emperor in the Chinese capi-
tal, and assign his adopted son to rule over Korea, before subjugating other coun-
tries like Ryukyu, Taiwan, and the Philippines.^45 When King Sonjo rejected his
demands to provide safe passage for Japanese forces to China, Hideyoshi finally
decided to invade Korea with a force of 281,840 men, of which the invading
contingent numbered 158,700, and the initial attacking party three corps of 52,500
men, who landed near Pusan on May 23, 1592.46 This large fighting force had
been hardened by a long period of combat in Japan's internal wars, its ashigaru
foot soldiers had been trained in the use of muskets and firearms introduced by
the Portuguese to Japan in T 543, and even its peasant baggage carriers were skilled
in the use of firearms, castle and fortress construction, and siege tactics against
walled towns.^47
Yu Songnyong, the Korean chief state councilor during the invasion, praised
the superior tactical organization of Japanese military units because the van-
guard unit that engaged the enemy was always backed up by two units on its
left and right wings to envelop the enemy, and those two wings also had two
additional units behind them. In addition, these individual Japanese units were
subdivided into three parts. When approaching a Korean force, the banner unit
in the van divided in two to envelop the enemy, the middle unit armed with mus-
kets would fire a volley to break up the Korean ranks, and the rear unit armed
with swords would then flank the Koreans on the left and right and pursue them
when they took flight, decapitating as many of them as they could. Korean units,
by contrast, simply concentrated their troops in one place and moved forward,
and when they saw that they were about to be surrounded hy superior Japanese
tactics, they usually lost heart and took flight.^48
After Hideyoshi's forces landed at Pusan on May 23, 1592, they pushed past
Korean defenses and took Seoul in three weeks. Outside of a number of naval
victories the only advantage the Korean forces gained on land was to block Japan-