North Korea started the Korean War in 1950 with a surprise attack on the south.
This nearly drove South Korean and American troops into the sea, but the USA poured in reinforcements and the south recovered.
By September it had regained numerical superiority and was in a position to counterattack.
USA General Douglas MacArthur envisioned a surprise attack of his own, an amphibious landing at Inch'on,
similar to many amphbious operations that he had conducted in World War II.
If successful, it would cut the supply lines of the North Koreans operating in the south.
He had planned the attack at the start of the war, however had to postpone it several times until the advance of the northern forces had been stopped.
Other generals were skeptical, pointing out the problems of narrow approaches, mudflats, strong currents and strong seawalls.
Also, the operation would require the use of almost all available troops, leaving no reserves to handle any counteroffensives.
The Americans scraped together an attack force by combining units, adding inexperienced conscripts and recommissioning equipment.
Before the attack false information was spread to lure the North Koreans into thinking that the landings would take place at Kunsan, far more to the south.
Meanwhile scouts infiltrated Inch'on and helped direct a naval bombardment and clearing of a handful of mines.
The assault took shape in three landings at Inch'on, timed to match the tides.
Around 250 ships, 40,000 troops and several thousand vehicles took part on the UN side, however the number of soldiers and tanks involved in the initial attacks were much smaller.
The North Koreans had 1,000 infantry at Inch'on, 500 at Kimpo airfield and 5,000 in the city of Seoul,
though they shifted around 1,000 to the harbor shortly before the assault.
MacArthur claimed that the deception had worked, but the North Koreans simply lacked the strength to properly garrison their wide front.
So instead they trusted the natural defenses of the Inch'on geography.
This proved to be a mistake.
The marines landed with ladders and a few tanks.
The small North Korean garrison at the harbor, lacking minefields and artillery, was quickly overwhelmed.
The attackers immediately started to construct a pontoon dock and unload more tanks, artillery and supplies.
They also swiftly conquered Kimpo airfield so that their air force could operate from there.
There were a few counterattacks from the North Korean army and air force, but these were feeble and easily repulsed.
Immediately behind the harbor lay Seoul, the South Korean capital and a great strategic target.
MacArthur wanted to liberate the city first, to boost the morale of the South Koreans.
However the advance, slowed by cautious street fighting against stiffening resistance, took more than a week.
This allowed some 40,000 North Korean troops, which had been stationed to the south of the city, to retreat back north.
This marred the otherwise solid victory of MacArthur.
War Matrix - Battle of Inchon
Cold War 1945 CE - 1991 CE, Battles and sieges