Key point: Pyongyang's plans did not go as hoped.

Thirty-one shadows crept up to the fence in the cold winter night, cut it and slipped through, walking into the American side of the demilitarized zone that buffers North and South Korea. It was January 1968 and the North Korean special operations troops were headed south.

The men were from the 124th Army Unit, an elite military organization charged with carrying out guerilla operations against the North’s sworn enemies to the south.

They were dressed in coveralls with South Korean military uniforms underneath and heavily-armed, each soldier carrying a submachine gun, a pistol, eight grenades and an anti-tank mine. Their missions, in the words of one the troops, was to “cut off [South Korean president] Park Chung-hee’s head and, after that, to shoot his important lieutenants to death.”

As the team crossed into the DMZ, North Korean propaganda radio thundered with a call from North Korean president Kim Il-sung to strike the United States and “split its forces to the maximum degree.” The world, he implored, must “tie the U.S. up wherever it put its feet so that it cannot move around freely.”

The 124th’s attempt to assassinate South Korean dictator Park Chung-hee would be the most dramatic act in Kim’s roughly three year campaign to make good on the pledge to be thorn in the side of the United States and its allies. Since the fall of 1966, he had unleashed a campaign of guerrilla warfare and subversion aimed at trying to sow chaos within the South Korean interior.

The raiders would bring that war right to Park’s doorstep, but no farther. The failed attempt would prove the high water mark of Kim’s campaign, after which the hopes of a popular uprising would fade.

Once through the fence, the raiders from the 124th found themselves in a section of the DMZ patrolled by American troops from the 2nd Infantry Division.

North Korea had used the warm weather infiltration seasons of 1967 to launch a series attacks along the 38th parallel. In May, satchel charges planted by operatives from the North had ripped through a 2nd Infantry Division barracks, killing two American soldiers. By the end of the year, North Korean attacks would claim the lives of 16 members of the division.

After two days in the DMZ, the raiding party came across four woodcutters. The encounter was a threat to the mission — South Korean citizens often informed on suspected infiltrators. But it was January and digging graves to bury the men in the frozen earth would’ve been difficult and time-consuming. Their families might notice the woodcutters’ absence and call the police.

The soldiers instead grabbed the men and conducted an impromptu propaganda session, inveighing against Park and the United States and promising that unification at the hands of the great Democratic People’s Republic of Korea would soon be at hand.

Before leaving, they warned the woodcutters not to tell anyone about their meeting. Nonetheless, the civilians quickly told South Korean police what they had seen, kicking off a manhunt to find the team.

As South Korean police searched for a team of North Korean guerillas, the soldiers from the 124th entered Seoul, dropped their coveralls leaving them dress in South Korean military uniforms for the final leg of their mission. As the soldiers approached within 800 meters of the presidential residence, a policemen challenged them. When their cover story fell apart, they opened fire — and all Hell broke loose.

Two members of the raiding party were killed in the initial confrontation and over the next few days, all but two more of the rest of the teams would be wiped out as they fled, either killing themselves with grenades to avoid capture or dying at the hands of the South Korean and American security forces pursuing them.

One of the survivors made it back to North Korea, where he’s now a general in the Korean People’s Army.

The other, Kim Shin-jo, was captured by South Korean forces. Kim had fled up Iwang Mountain as he was chased by South Korean soldiers, dropping all of his weapons except for a single grenade kept to finish himself off at the last moment. Kim later claimed that a last second “desire to live” saved him from suicide once he was surrounded by 20 South Korean troops.

His last grenade, however, was defective, leading some to doubt the story.

South Korean officials later offered Kim up to reporters who peppered him with questions about his mission, conditions in North Korea and what he thought was better about life in the North over the South. His answer — “Besides kimchi and girls? Nothing.”

Decades later, he would receive a pardon from the South Korean government and a job as a human rights advisor to South Korea’s Grand National Party. Today, he’s a Presbyterian minister in a large congregation near the capital city he once stormed.

The raid targeting Park came as a terrible shock to South Korean society, but the idea of an assassination attempt wasn’t completely out of the blue, at least not to the CIA. The Agency had picked up hints about North Korean assassination plots at least six months prior to the Blue House raid.

Vice Pres. Hubert Humphrey was scheduled to attend Park’s inauguration in July of 1967 and the CIA passed them along in an assessment of security conditions in the ROK written in advance of the trip.

“We are aware of several North Korean direct threats against the life of President [Park] and the dispatch of occasional agent teams charged with this mission,” it warned. “The possibility of another Communist effort of this sort during the inaugural period cannot be ruled out.”

But there was another shock to come. Two days after the Blue House raid, North Korea seized the USS Pueblo, a U.S. Navy spy ship listening to communications off the eastern coast of the Korean peninsula. North Korea killed one member of Pueblo’s crew in the incident and took the remaining 82 back to North Korea where they’d stay for a year until negotiations between the U.S. and Pyongyang led to their release.

Park was furious. For over a year, the North had been kidnapping South Korean fishermen, had sunk a ROK navy ship in 1967 trying to protect them and was still killing U.S. and South Korean troops along the DMZ. In his mind, the wave of violence was the opening act for another Korean War.

In a conversation with former Deputy Secretary of Defense Cyrus Vance, acting as a White House envoy, Park shared his suspicions. “Now the pattern is changing,” he said, according to a summary of the talks. “[The North Koreans] are setting the stage for open aggression against South Korea.”

But U.S. officials didn’t see it that way. In reports over the weeks following the incidents, the CIA averred that the Blue House raid was “probably the beginning of a stepped-up Communist terrorist campaign” but that “nothing the North Koreans have done suggests they are about to embark on large-scale hostilities.”

Three days after the raid, U.S. Navy rear admiral John Smith of the Military Armistice Commission, the mechanism set up to oversee the armistice at the end of the Korean War, held a meeting with his North Korean MAC counterpart, Gen. Pak Chang Kuk, to protest the North Korean attacks and demand an end to the provocations and the return of the Pueblo crew.

Smith flopped down a map showing the route of the Blue House raiders into the ROK as well as photographs of their corpses and the weapons they used in order to prove Pyongyang’s complicity in the assassination attempt. If the North Koreans were intimidated by the gesture, they certainly didn’t show it.

A subsequent State Department summary of the meeting noted that the North Korean side seemed downright and openly laughed at Smith’s demands.

In the meantime, there was the threat of further guerrilla activity from North Korean commandos. In his February meeting with Vance, Park said South Korean intelligence now knew that the 124th was divided into 80 or 90 teams of 30 and he worried that they could target South Korean airfields, dams and factories.

Details about the 124th Army Unit from Kim Shin-jo offered a glimpse of the North Korean special operations outfit that now had the ROK in its crosshairs.

Prior to entering the 124th Army Unit, Kim had been a Korean Workers’ Party member and his parents were still alive and living in the North along with his three sisters. He had served in the KPA and was selected for service in the 124th.

It was an elite outfit and only those with “very excellent records in the armed services, in addition to mighty physical strength” were chosen to join, he said. Once in the unit, troops were given heavy instruction in jiu-jitsu, boxing and marksmanship.

The details shared by Kim are consistent with what’s now known about the unit. “In general, you had to be a party member in very good standing and deemed reliable, politically, to be a part of the 124th Army Unit,” says Joseph Bermudez, an expert on North Korean military and intelligence issues. “Most of them had to have living family in the North to ensure their loyalty.”