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During communist North Korea’s surprise invasion of democratic South Korea that began June 25, 1950, Northern forces crossed the 38th parallel dividing the two countries, quickly captured the neighboring nation’s capital, Seoul, and rolled south like an unstoppable juggernaut. Led by a brigade of Soviet-built T-34tanks, over 230,000 soldiers of the North Korean People’s Army (NKPA) smashed through all attempts that the 65,000-manU.S.-trained Republic of Korea (ROK) army mounted to stop them. Even U.S. President Harry S. Truman’s commitment of American ground troops to the ongoing combat in early July disastrously failed to slow the NKPA advance.

By the beginning of August, the North Korean offensive had pushed ROK and U.S.forces into a 90-by-60-mile enclave near Pusan at the southeastern tip of the Korean peninsula. (See Korea, 1950 map, p. 57.)Inside the “Pusan perimeter” were the embattled troops of U.S. General Walton Walker’s 8th Army, consisting of five battered ROK divisions, four under strength U.S.Army divisions, and the U.S. Marine Corps’4,700-man 1st Marine Provisional Brigade.Desperate to eliminate these last remaining forces and thus overrun the entire peninsula, NKPA tank and infantry units continued to launch powerful attacks.

Walker’s 8th Army was able to maintain its tenuous hold on the perimeter with stubborn defensive fighting and limited counterattacks to regain lost ground. However, an enemy attack launched around the first week of August forced a dangerous “bulge” in the southwestern sector of the perimeter. NKPA4th Division advanced across the Naktong River, pushed back the outnumbered U.S.24th Infantry Division defending the Naktong line, and seized a bridgehead east of the river. From this position, NKPA forces had an opportunity to strike east toward the vital port of Pusan, whose capture would have collapsed the entire defense of the perimeter.

Armchair General® takes you back to August 17, 1950, at the southwest sector of the Pusan perimeter two miles east of the Naktong River, where you will play the role of U.S. Marine Corps Captain Ike Fenton,commander of B Company, 1st Battalion,5th Marine Regiment, 1st Marine Provisional Brigade. Your mission is to attack and seize enemy-held high ground on Obong-niRidge. By capturing and holding this key terrain, your troops will prevent North Korean forces from expanding their bridgehead and striking east to capture the port of Pusan.

If your attack should fail, however, 8th Army’s tenuous toehold on the Korean peninsula will be placed at great risk, and U.S. and ROK forces ultimately could be dealt a disastrous defeat.


North Korea’s decision to attempt to unite the Korean peninsula under communist rule by force was in large measure prompted by the misjudgments of the Truman administration. Fixated on the threat that the Soviet Union poses to Europe in these early years of the Cold War, Truman and his senior advisers have placed little political and military emphasis on the defense of Asian nations. Although U.S. military advisers have trained and equipped the ROK army since the peninsula was divided between the democratic South and communist North at the end of World War II, the administration’s focus in the region has been on rebuilding Japan.

Seven months ago, Truman’s Secretary of State Dean Acheson delivered a speech to the National Press Club in which he specifically placed South Korea outside of the strategic defense perimeter in Asia that the United States was committed to defend. Yet, stung by the loss of China to Mao Zedong’s Communists in 1949, the U.S. administration realized it could not afford to allow another Asian nation to fall to communism. Thus, shortly after the North Korean invasion began, Truman, backed by a United Nations Security Council resolution, ordered General of the Army Douglas MacArthur, supreme commander in the Far East, to commit U.S. air, naval and ground troops to the defense of South Korea.

However, soon after MacArthur committed the initial contingent of U.S. ground troops in the first week of July, another fateful misjudgment by the Truman administration was painfully exposed. The president’s rapid post-World War II demobilization of the magnificent U.S. military that had conquered Nazi Germany and Imperial Japan, coupled with crippling defense budget cuts, left the American military a disastrously weakened “hollow force.”

MacArthur’s challenge now is to mobilize, train and equip the forces necessary to mount a devastating counterstroke to defeat the NKPA and save South Korea. Yet such an effort requires time, and time will surely run out if Walker’s 8th Army is unable to hold the Pusan perimeter.


The weapons, tactics and combat operations employed in the fighting in Korea have thus far been the same as those used in World War II. In fact, many participants on both sides are veterans of that previous war’s fighting. Despite Truman’s desire to fight a limited war – he has characterized U.S. involvement as a “police action” – American GIs and Marines embroiled in the intense combat are cynically referring to the situation in Korea as “World War Two and a Half.” The war may seem “limited” to politicians and bureaucrats in Washington, D.C., but that is hardly the word troops fighting and dying in the Pusan perimeter would use to describe it.

Like the rest of Walker’s 8th Army American units, your Marine B Company is equipped with World War II-era weapons and largely filled with veterans of the previous war, many of whom are reservists that were rapidly recalled to active duty to meet the crisis in Korea. The company is composed of a small headquarters element,three infantry platoons and a weapons platoon. Each infantry platoon contains about 30 Marines armed with .30-caliber M1 Garand rifles, a few .30-caliber M1carbines and some hand grenades. Attached to each platoon is a two-man team armed with a 3.5-inch M20bazooka capable of knocking out tanks and destroying bunkers and strong points. The infantry platoons are supported by fire from the weapons platoon’s six .30-caliber M1919A4machine guns and three60 mm mortars.

Your company can request additional fire support from the81 mm and4 . 2 – inch mortars of1st Battalion’s Weapons Company, the 105 mm howitzers of 11th Marine Artillery Regiment, and airstrikes (fragmentation and napalm bombs) from Marine close air support operating from U.S. Navy aircraft carriers offshore. Although 5th Marine Regiment has some M26 Pershing tanks, they cannot operate on ridges or hills and are restricted to roads and flat terrain.

The enemy in your sector consists of infantry battalions of NKPA 4th Division, 18th Regiment. Primarily light infantrymen, the NKPA soldiers are armed with Soviet-built weapons: 7.62 mm Mosin-Nagant bolt-action rifles and carbines, 7.62 mm PPSh 41/43 submachine guns, and hand grenades. Supporting weapons include 7.62 mm Degtyaryov light machine guns, 7.62 mm Goryunov SG43 medium machine guns, and 82 mm mortars. The North Korean units in this sector have no tanks or air support and have only limited artillery support.

Although NKPA ranks have been thinned by nearly two months of heavy combat, they remain a formidable and dangerous foe. The enemy soldiers are skilled and tenacious fighters in both offense and defense, and their fighting spirit has been buoyed by a string of victories over ROK and U.S. forces.


Until 20 minutes ago, you were B Company’s executive officer and thus second in command of the unit. However, just as your company commander, Captain John Tobin, was completing his briefing to you on the attack mission, he was severely wounded by a sudden burst of enemy machine-gun fire. Tobin was quickly evacuated by medical corpsmen, leaving you in charge of the company.

B Company’s mission is part of 1st Battalion’s attack to seize and hold Obong-Ni Ridge, a narrow strip of dominating ground beginning just south of the village of Tugok and running generally north-south for 1.2kilometers. The surrounding terrain is flat and open, consisting mainly of rice paddies and cotton fields. The objective of your attack is the approximately 600-meter northernmost section of the ridgeline, including key high ground at hills102 and 109.

At the same time that your attack is to commence, 1st Battalion’s A Company will strike to seize the ridgeline south of your objective. Meanwhile, to the north of the battalion’s sector, U.S. Army 9th Infantry Regiment will assault Finger Ridge, west of Tugok. With Obong-Ni Ridge and Finger Ridge in American hands, North Korean forces east of the Naktong River will be contained and unable to launch further attacks that could threaten Pusan port.

With precious little time left before the operation is scheduled to begin, you gather your platoon leaders at the company command post on Observation Hill. Once they  arrive, you begin briefing them on the mission, using a map to point out the company’s objective and the key terrain features.

“The North Koreans on our section of the ridgeline,” you explain, “are positioned in foxholes and strong points both along the ridge and on the reverse slope, which we can only hit by using high-angle fire support weapons such as mortars and howitzers. The terrain on the ridge won’t offer our Marines much cover since it’s rocky and mostly bare with only a few scattered low shrubs and bushes. Thus, once the attack kicks off, our guys must move as quickly as possible to close with the NKPA forces to limit the amount of time they’re exposed to enemy fire.

“Now, listen closely as I brief you on three different courses of action I’m considering for our attack. Feel free to give me your candid assessment of each. Afterward, I will decide which plan we will implement.”


“My first course of action,” you begin, “is to launch 1st and 2d platoons in a ‘right hook’ against the ridge’s north flank and then attack south along the ridgeline. First Platoon will take the lead and capture Hill 102, and then 2d Platoon will continue the attack to seize Hill 109. Meanwhile, 3d Platoon will remain in reserve to be committed on my order, and Weapons Platoon will support the attack with machine-gun and mortar fire from the forward slope of Observation Hill. We will receive additional fire support from the 81 mm mortars of 1st Battalion’s Weapons Company, airstrikes by Marine close air support, and the 105 mm howitzers of 11th Marine Artillery Regiment.”

Lieutenant Taylor, leader of 2d Platoon, replies, “Captain, I’m worried that attacking north to south along the narrow ridgeline will greatly restrict our room to maneuver and allow the enemy to concentrate fire on our lead elements. If 1st Platoon bogs down, it could block my platoon’s forward progress and then our entire attack might stall or even fall apart.”

In response, Lieutenant Schryver, leader of 1st Platoon, responds, “I think the restricted area along the top of the ridgeline is actually a disadvantage for the enemy. It prevents the North Koreans from moving additional troops to defend Hill 102, and those farther south will be unable to engage us with direct-fire weapons because of the intervening high ground.”


“The second option,” you continue, “is to launch an attack ‘by the book’: two platoons up and one platoon back in a frontal assault targeting two hills simultaneously. First and 2d platoons will advance abreast along a front parallel to the ridgeline, with 1st Platoon on the left attacking Hill 109 and 2d Platoon on the right attacking Hill 102. Once the platoons have seized these key high points, they will send squads to clear the ridgeline between them. Meanwhile, 3d Platoon will be held in reserve, prepared to reinforce either 1st or 2d platoon on my order. Fire support for this plan will be the same as in COA One.

Taylor enthusiastically responds, “Captain, attacking both key terrain features simultaneously certainly seems to be the quickest way to accomplish our mission. And I like that this plan provides flexibility by having 3d Platoon in reserve, ready to be committed if either 1st or 2d platoon bogs down.”

Lieutenant Brown, Weapons Platoon leader, appears concerned. “Captain,” he interjects, “under this course of action my machine guns and mortars will be required to fire over the heads of our advancing Marines, as will our fire support from the mortars and 105s from 1st Battalion and 11th Marines. This puts our guys at risk of being hit by friendly fire, especially as they close on the objective.”


“The final plan I’m considering,” you conclude, “is to go ‘all in’ with all three of our platoons attacking abreast in a frontal assault to seize our entire sector of the ridgeline at a single stroke. From left to right, 1st, 2d and 3d platoons will line up parallel to the ridgeline. Supporting fire from Weapons Platoon, as well as all other fire support, will be the same as in COA One.”

Lieutenant Morris, leader of 3d Platoon, replies, “Captain, in my opinion this plan gives our attack the best chance to succeed. Launching all three platoons at once maximizes our combat power against the enemy defenders and fixes them in place, thereby preventing them from shifting forces to reinforce any threatened area.”

Brown appears to be ready to speak again – undoubtedly to warn you about the risks of firing over the heads of your attacking troops – but you cut him off by announcing, “All right, I’ve heard enough. Go and prepare your platoons for the attack. In 10 minutes I’ll let you know which plan I’ve chosen. Good luck, Marines.”

What is your decision, Captain Fenton?


Andrew H. Hershey holds a doctorate in medieval history from the University of London. He contributes to the “USMC Gazette” and is a fourtime winner of its Tactical Decision Game design contests. He also designs World War II tactical-level wargames for Heat of Battle and Le Franc Tireur.

Originally published in the January 2015 issue of Armchair General.