An Khe Pass (April 1972): to open the road, take the hill first

2026-10-13 · 1972-04-11 – 1972-04-27

Overview (BLUF)

On 11 April 1972 the PAVN 3rd Division's 12th Regiment blocked the An Khe Pass on Route 19, the road linking Qui Nhon and Pleiku. The Cavalry Regiment of the ROK Capital Division (the Tiger Division) was sent in. The fortified positions on Hill 638, which overlooks the pass, held out through napalm strikes, and after ten days 2nd Battalion's attack had made no headway. On 22 April 2nd Company broke into the enemy's first line on its fourth attempt of the day, and the hill was secured around the 24th. The road was officially declared open on the afternoon of the 27th.

Two points stand out. The regiment separated its objective, the road, from the decisive terrain, the hill that overlooked it. And where the ground ruled out formations, what set the pace of the attack in the end was where the small-unit leaders stood.

Background and Strategic Context

North Vietnam opened its Easter Offensive at the end of March 1972. In the Central Highlands, Tan Canh and Dak To were attacked on 12 April, and on the coast of northern Binh Dinh province the PAVN 3rd Division pressed the ARVN 22nd Division. By 2 May the districts of Hoai An, Hoai Nhon and Tam Quan were in PAVN hands (Wikipedia cross-check).

Route 19 is the main supply line from the coastal base at Qui Nhon up to Pleiku in the highlands. AP reported at the time that the communists aimed to take the highlands and Binh Dinh and cut South Vietnam at its waist; the Korean encyclopedia likewise says the PAVN sought to split the Central Highlands east from west. With the An Khe Pass shut, ARVN supply in the highlands was at risk. The Tiger Division, responsible for the area, was given the task of reopening the road.

Terrain and Weather

The An Khe Pass lies on a spur of the Annamite range about 600 m high. It is not tall, but it is very steep, and tree roots and boulders quickly broke up any assault formation (encyclopedia). Hill 638 looks down on the pass and dominates Route 19 (Figure 1). The enemy had dug fortified positions on the top and the slopes. Vehicles caught in an ambush two weeks earlier still sat on the road. April is the tail end of the highland dry season, which probably favoured air support, but we found no weather record for the days of the battle.

Sketch map of the An Khe Pass battle: PAVN positions on the top and slopes of Hill 638 north of Route 19, fire from the hill onto the road, ROK company attacks climbing the slopes from the east and the 22 April breach, ambushed vehicles on the road, and the infantry company behind APCs reaching the pass summit — Figure 1. An Khe Pass, sketch map (11–27 April 1972). A schematic based on the scenario map; terrain, distances and positions are approximate — our own work, based on sources 1–4

Forces and Dispositions

ROK: The Cavalry Regiment (1st Cavalry Regiment) of the Capital Division. 2nd Battalion had the attack on Hill 638, backed by APCs, division artillery and close air support. Engineers were to clear the road once the high ground was held. Detailed organization, such as how many companies were committed, still needs checking against the official history.
PAVN: The 12th Regiment of the 3rd ("Sao Vang") Division. It dug in on the high ground either side of the pass, above all the top and slopes of Hill 638, and cut the road. The division's other regiments are said to have attacked ARVN forces around Bong Son to the north (Korean secondary source, unverified).

Course of the Action

Road cut, first attacks (11 April): The Cavalry Regiment engaged the 12th Regiment in the An Khe valley. The objective was the high ground commanding the road.
Fight for the hill positions (mid-April): Company attacks climbed the slopes one after another. Napalm strikes blackened the hill, but the positions held; by the 21st, 2nd Battalion's attack had been stalled for ten days.
The breach of 22 April: At 0800 2nd Company took the lead. Attacks at 1000 and 1300 failed, and a third at 1500, with two-man teams working up the slope, was also stopped by the ground. In the fourth attack, from 1510, the company commander moved up to a platoon leader's position, platoon leaders to squad leaders' positions, and so on. At about 1815 the 1st Platoon leader, Lieutenant Im Dong-chun, broke into the enemy's first line with grenades. Wounded in the leg by fragments, he pressed on toward the second line and fell there (Figure 2).
Hill secured (23–24 April): After three days of close-quarter fighting, Hill 638 was retaken on Monday the 24th (AP and UPI reports). The veterans' association marks the same day as the day the hill was secured.
Road reopened (26–27 April): On the 26th an infantry company moved behind APCs to the top of the pass, met no opposition, and soon returned to the main line. A Korean spokesman announced that day that the pass was clear, but reports from Qui Nhon said destroyed culverts still kept the road closed. On the 27th engineers built bypasses round the culverts, filled bomb craters and moved the ambushed vehicles off the road. The pass was officially declared open that afternoon, too late for traffic to move safely; only tanks went through.

Two time axes: the whole battle from 11 to 27 April 1972, and the 2nd Company attack on 22 April hour by hour. On 22 April the attacks at 1000, 1300 and 1500 failed, and the fourth attack from 1510 breached the first line at about 1815 — Figure 2. The whole battle (top) and the 22 April attack (bottom). The 24 April date for securing the hill is the same in the AP report and the veterans' commemoration — our own work, based on sources 1–6

Decision Point Analysis

Decision 1: How to open the road (ROK Cavalry Regiment) The options were (a) push a convoy through under APC escort, (b) attack the blocking positions on the heights overlooking the road, (c) seal off the pass and leave it to air and artillery, or (d) hand it to ARVN and guard only the base area. The regiment chose (b). Leave the hill alone and every convoy would come under fire from above. The judgment was sound, but attacking fortified positions took nearly two weeks. This is the scenario's first phase.

Decision 2: Where and how to block (PAVN 3rd Division and 12th Regiment) The PAVN could keep ambushing on the road, occupy the road itself, or fortify the heights that overlooked it. The 12th Regiment cut the road with an ambush and then built fortified positions on the top and slopes of Hill 638. The aim appears to have been to tie down a Korean regiment with a small force while the division's main body pressed ARVN in northern Binh Dinh. The hill held for nearly two weeks and the road stayed shut for as long. In the end the hill was lost, and the Korean encyclopedia claims the regiment lost about a third of its strength (a Korean claim).

Decision 3: Whether to keep a stalled attack going (2nd Battalion and 2nd Company, 22 April) After three failed attacks that afternoon, the options were (a) halt and leave the hill to air and artillery for a day, (b) shift the main effort to another ridge, (c) keep attacking with leaders out in front, or (d) hold in place and wait for reinforcement. The company chose (c), apparently judging that where the ground broke up formations, the leaders' position set the pace of the attack. The first line fell at dusk, but the platoon leader who went first and his men paid heavily. Phases 3 to 5 of the scenario cover this decision.

Decision 4: When to open the road once the hill was taken (ROK) The options were (a) declare it open at once and start the convoys, (b) clear every remaining ridge first, or (c) check the pass with APCs and infantry and then bring in the engineers. The regiment took (c), and even when it declared the road open on the 27th it let only tanks through that day. A day passed between the announcement of the 26th and the moment the road could actually be used. These are the scenario's phases 7 and 8.

Lessons

Decisive terrain: The objective was the road, but the decisive terrain was Hill 638. To open a road, first take the ground that overlooks it.
Mission command and leading from the front: On ground where formations fell apart, junior leaders who understood the commander's intent (reopen the road) and went first are what moved the attack. The price was heavy losses among those leaders.
Integrating fire and maneuver: Napalm and artillery alone did not destroy the fortified positions. The last few hundred metres had to be cleared one position at a time by infantry under covering fire.
Sustainment and engineers: Taking the hill did not finish the mission. Engineers and mobile forces had to follow at once to turn a tactical gain into an open supply line.
Intelligence and announcements: The announcement that the pass was clear and the road's actual condition did not match. Road status has to be judged from checks on the ground.

Unresolved Questions

Resistance after the hill fell: the hill was retaken on the 24th, but the pass summit was reached only on the 26th and traffic moved only on the 27th. Reports differ on how much resistance remained in between.
ROK losses: the ROK official interim figure of April 1972 (51 dead, 115 wounded), unofficial sources cited by AP (110 dead, 384 wounded) and the veterans' association (173 dead, over 400 wounded) differ widely. The MND history of the Korean forces in Vietnam needs to be checked.
The number of companies committed, the course of the fighting battalion by battalion, and the size of the 11 April ambush could not be confirmed.
The attack by the 3rd Division's other regiments around Bong Son rests only on a Korean secondary source.

Take command of 2nd Battalion, Cavalry Regiment, in the "An Khe Pass" scenario and make the decisions about the hill and the road yourself.

Sources

Academy of Korean Studies, entry on the 1st Platoon leader of 2nd Company (Im Dong-chun), Encyclopedia of Korean Culture (citing the MND history of the Korean forces in Vietnam, vol. 10, 1985). https://encykorea.aks.ac.kr/Article/E0047425 (accessed 2026-10-13)
AP, "ROK Casualties Higher?", Pacific Stars and Stripes (1972-04-29), reprint. https://thebattleofkontum.com/stars/032.html (accessed 2026-10-13)
AP, "Red Drive Slowed in Viet Highlands", Pacific Stars and Stripes (1972-04-28), reprint. https://thebattleofkontum.com/stars/14.html (accessed 2026-10-13)
UPI, "N. Viets March Toward Showdown", Pacific Stars and Stripes (1972-04-27), reprint. https://thebattleofkontum.com/stars/10.html (accessed 2026-10-13)
AP (Seoul), report of official praise for the Tiger Division's recapture of Hill 638 on Monday 24 April, Pacific Stars and Stripes (1972-04-28), reprint. https://www.thebattleofkontum.com/stars/023.html (accessed 2026-10-13)
Ilgan Sports, report on the An Khe Pass memorial service and the veterans' association (2026-07-15). https://isplus.com/article/view/isp202607150046 (accessed 2026-10-13)
Wikipedia, "Easter Offensive" (cross-check; northern Binh Dinh and Kontum). https://en.wikipedia.org/wiki/Easter_Offensive (accessed 2026-10-13)
Wikimedia Commons, file page for the An Khe Pass photo (CC BY-SA 3.0). https://commons.wikimedia.org/wiki/File:%C4%90%C3%A8o_An_Kh%C3%AA,_Gia_Lai-B%C3%ACnh_%C4%90%E1%BB%8Bnh.JPG (accessed 2026-10-13)