MILITARY REORGANIZATION 529
of the wall, or the use of peepholes along the base as recently introduced into
China. The Chinese also used special cannon emplacements in the moats out-
side the walls that were particularly effective. These also had yet to be adopted
in Korean wall construction. Yu also recorded in his "Precautions Against Attack"
(ChinRbirok) that he had devised his own wall architecture and dimensions one
day during Hideyoshi's invasions while sitting on the banks of the Ch'ongch'on
River near Anju, He proposed constructing gun holes and turrets separated by
six to seven hundred paces with a pile of cannon balls stacked by the big guns
"like chicken eggs."
"Then when the enemy approaches the walls, he will be hit by a cross fire
from the guns. Not to speak of men and horses, even metal and stone could not
escape being pulverized by this .... All you would have to do is to have several
dozen men man the gun turrets and the enemy would not dare draw near."7^2
Yu Hyongwon recorded, however, that despite the wisdom ofYu Songnyong's
plan for a field of cannon fire, the government failed to adopt it, not only dur-
ing the invasions but even to his own time. Just as Ch'i Chi-kuang had been
beleaguered by conservatives in Ming China who felt that his new methods of
wall and turret construction were newfangled and outlandish, so too did Yu
Songnyong have to buck the resistance of traditionalists,7'
Yi Hyongsok in his magnum opus on the Imjin War commented that Yu
Hyongwon's essay on wall construction was particularly valuable because it
emphasized not only the proper construction of mountain forts (sansong) which
were so popular in Korean defensive strategy. but because his advocacy of wall
construction around the district towns in the plains rectified one of the major
Korean strategic deficiencies during Hideyoshi's invasions. At that time the main
defensive policy used in the face of the superior advancing Japanese forces was
to "strengthen the walls and clear the countryside," which did not refer simply
to clearing thc wet and dry fields of all peasants, food, and property and bring-
ing them inside the walls of the district towns, but to moving the entire popu-
lation and their property to the mountain forts located at remote distanccs from
the villages of the peasants. Because of the general reluctance to move to such
quarters, the peasants either neglected to move, failed to maintain the mountain
forts in good repair, or delayed their movement to the mountain forts to the last
possible minute. The result in most instances was that the advancing Japanese
forces were soon upon the villagers before they could seek shelter, and they were
forced to flee to the hills and remote valleys and live in hiding without adequate
shelter. Even when the policy was followed, it meant that the Korean military
commanders abandoned the lowlands and the towns, for the mountain forts, leav-
ing the Japanese unopposed access to the towns and the main travel route from
Pusan through Hansong (Seoul), Kaesong, and Pyongyang. 7 .)
Finally, Yu appears to have been unaware of the main constraints against wall
and fort construction in the 1650s. One of the main restrictions was the poor
economy and opposition by Kim Yuk to the debilitating effects of King Hyo-
jong's vast reconstruction plans. Kim's main argument, that demanding labor