A CCF fire team mans a 7.62 mm
Ruchnoy Pulemyot DP (Degtyaryova pakhotnyi) in a
front-line cave.
When truce talks began, China
spent a year rebuilding their armies,
constructing an underground system of
interconnected caves and tunnels behind their
main defensive lines, in such strength as to be
invulnerable to our artillery except when they
sent forces above ground to attack our outposts.
By July, '52, the enemy lines were virtually
impregnable, except for their own outposts. Even
in those outposts, the Chinese and North Koreans
dug deep cave systems behind their trench lines,
making any assault very costly.
Even with her large
manpower resources, it was an awesome
accomplishment for China to build the
interconnecting cave-tunnel complex which
supported her main-line defenses. ("A total
of 1,250 km. of tunnels and 6,240 km. of trenches
involving the shifting of 60 million cubic meters
of rock and earth were dug along the front"
- Marshal Peng Dehuai)