Korean War: Armed Forces of North and South Korea 1950 (2)

The North Korea People’s Army had been from the beginning under the supervision of the Soviets. At first the Peace Preservation Corps had undertaken the organization and training of a military force. Then, when the Soviets began to withdraw their occupation forces in February 1948, the North Korean Government established a Ministry of Defense and activated the North Korea People’s Army. Soviet instruction and supervision of the Army continued, however, after the withdrawal of Soviet forces from North Korea. One prisoner stated that every training film he ever saw or used had been made in the USSR. About three thousand Russians were active in the Army program before June 1950. In some instances as many as fifteen Soviet officers served as advisers on an N.K. infantry division staff. The adviser to a division commander reportedly was a Soviet colonel.

The Soviet diplomatic mission to North Korea, apparently organized in January 1949, became the post occupation body for Soviet control of the country. By June 1950 every member of the Soviet diplomatic staff in North Korea was either an army or an air force officer. Colonel General Terenty F. Shtykov, commander of the Soviet occupation forces in North Korea and, after their withdrawal, the Soviet Ambassador there, apparently functioned as the senior Soviet officer in the country. Intelligence reports indicate that Premier Kim Il Sung received weekly instructions from the USSR through Ambassador Shtykov.

In June 1950 Kim Il Sung was Commander in Chief of the North Korean armed forces. His deputy was Marshal Choe Yong Gun. Both had left Korea in their youth, resided in China for long periods of time, and, ultimately, gone to Moscow for training. Kim Il Sung returned to Korea on 25 September 1945 under Soviet sponsorship, landing at Wonsan on that date with a group of Soviet-trained guerrillas.

For all practical purposes the North Korean ground forces in June 1950 comprised two types of units: (1) the Border Constabulary (BC or Bo An Dae) and (2) the North Korea People’s Army (NKPA or In Min Gun). The Border Constabulary, an internal security force, was organized, trained, and supervised by Soviet officials. It was uncommonly strong in political indoctrination and supported and promoted the Communist party line throughout North Korea. All officer training for the Border Constabulary was under the direct supervision of Soviet advisers on the school staffs.

The Border Constabulary had its beginnings as early as September 1945, when anti-Japanese and Communist Koreans, guerrillas who had fled from Korea and Manchuria to Soviet territory, came back to Korea and formed the nucleus of what was called the Peace Preservation Corps. It numbered about 18,000 men and drew its personnel mostly from Communist youth groups. Its officers were usually active Communists. In May 1950 the effective strength of the North Korean internal security forces was approximately 50,000, divided among the Border Constabulary, the regular police, and the “thought” police.

The Border Constabulary in June 1950 consisted of five brigades of uneven size and armament—the 1st, 2nd, 3rd, 5th, and 7th. The 1st Brigade numbered 5,000 men; the 3rd and 7th each had a strength of 4,000. These three brigades were stationed just north of the 38th Parallel. The 7th was in the west, deployed from Haeju to the coast, just above the Ongjin Peninsula; the 3rd was east of the7th, in the center from Haeju to the vicinity of Chorwon; and the 1st was at Kansong on the east coast. These three brigades, totaling 13,000 men, were armed and equipped to combat-infantry standards. The brigades each had six or seven battalions composed of three rifle companies each, together with machine gun and mortar companies, an antitank platoon, and the usual headquarters and service units.

The BC 2nd Brigade, with a total strength of only 2,600, was divided into seven battalions. It held positions along the Yalu and Tumen River boundaries separating North Korea from Manchuria and the USSR. This brigade had little heavy equipment and few mortars, machine guns, or antitank guns. The BC 5th Brigade, with a strength of about 3,000 men, had headquarters at Pyongyang, the North Korean capital. It was responsible for railroad security.

The North Korea People’s Army

The North Korea People’s Army in June 1950 constituted a ground force of eight infantry divisions at full strength, two more infantry divisions activated at an estimated half strength, a separate infantry regiment, a motorcycle reconnaissance regiment, and an armored brigade. Five of the infantry divisions and the armored brigade had well-trained combat personnel. Many of these soldiers were hardened veterans who had fought with the Chinese Communist and Soviet Armies in World War II. The North Korea People’s Army was officially activated on 8 February 1948.

Its first full infantry divisions, the 3rd and 4th, were established between 1947 and 1949; and its first armored unit, the 105th Armored Battalion, was established in October 1948. The latter increased to regimental strength in May 1949. Conscription for replacements and build-up of the North Korea People’s Army apparently began about July 1948.

After a meeting of USSR and Communist China officials, reportedly held in Peiping early in 1950 to explore the advisability of using the North Korea People’s Army for an invasion of South Korea, there was a rapid build-up of that Army. It increased its training program, transferred ordnance depots from urban to isolated rural sites, and readied hidden dump areas to receive supplies, weapons, and munitions of war from the USSR. At the beginning of this build-up there were in Korea about 16,000 repatriated North Koreans from the Chinese Communist Forces (CCF). In April 1950 Communist China returned 12,000 more veterans of the CCF to Korea where they formed the N.K. 7th Division (redesignated the 12th about 2 July 1950).

NOTE:Future reference to the two opposed Korean forces generally will be North Korean or N.K. and South Korean or ROK. The abbreviation N.K. will precede a numbered NKPA unit; ROK will precede a numbered South Korean unit.]

The Korean veterans of the Chinese Communist Forces made up about one third of the North Korea People’s Army in June 1950 and gave it a combat-hardened quality and efficiency that it would not otherwise have had. Five of the eight divisions in the North Korea People’s Army—the 1st, 4th, 5th, 6th, and 7th (12th) Divisions—had in their ranks substantial numbers of CCF soldiers of Korean extraction. The 5th, 6th, and 7th (12th) Divisions had the largest number of them. Also, many of the NKPA units that did not have rank and file soldiers from the CCF did have officers and noncommissioned officers from it.

Special mention needs to be made of the N.K. 5th, 6th, and 7th Divisions. In July 1949 the Chinese Communist Forces transferred all non-Koreans in the CCF 164th Division, then stationed in Manchuria, to other Chinese divisions and filled the 164th with Korean replacements. Near the end of the month the division, about 7,500 strong, moved by rail to Korea where it reorganized into the 10th, 11th, and 12th Rifle Regiments of the N.K. 5th Division.

At the same time, in July 1949, the CCF 166th Division moved to Korea and reorganized into the 13th, 14th, and 15thRegiments of the N.K. 6th Division. The story of the Koreans in this division goes back to 1942 when the Chinese Communists formed a Korean Volunteer Army largely with deserters from the Japanese Kwantung Army. This division had a strength of about 10,000 men when it entered Korea; there 800 replacements brought it to full strength.

In February 1950 all Korean units in the Chinese Manchurian Army assembled in Honan Province. They numbered about 12,000 men drawn from the CCF 139th, 140th, 141st, and 156th Divisions. Some of them had participated in the Chinese Communist advance from Manchuria to Peiping, and all were veteran troops. In the first part of April these troops moved by rail to Korea. In the Wonsan area these CCF veterans reorganized into the 1st, 2nd, and 3rd Regiments of the N.K. 7th Division.

In addition to these three divisions, the N.K. 1st and 4th Divisions each had one regiment of CCF veterans. All the units from the CCF Army upon arrival in North Korea received Soviet-type arms and North Korean uniforms and were retrained in North Korean tactical doctrine, which closely followed the Russian.

In March 1950 North Korea activated two new divisions: the 10th, around Manchurian-trained units, and the 15th, with men from three youth-training schools and veteran Communist officers and noncommissioned officers. Although activated in March, the 15th Division received most of its troops near the end of June—after the invasion had started. In early June the 13th Division was activated; the last one to be activated before the invasion of South Korea.

By June 1950, the 105th Armored Regiment had become the 105th Armored Brigade with a strength of 6,000 men and 120 T34 tanks. Its equipment—tanks, weapons, and vehicles—was Russian-made. The brigade had three tank regiments—the 107th, 109th, and 203rd—each with 40 tanks, and a mechanized infantry regiment, the 206th, with a strength of about 2,500 men. A tank regiment had three medium tank battalions, each having 13 tanks. The battalions each had three tank companies with 4 tanks to a company. Tank crews consisted of five men. Battalion, regimental, and division tank commanders each had a personal tank. The 105th Armored Brigade was raised to division status in Seoul at the end of June 1950 before it crossed the Han River to continue the attack southward.12

In addition to the 120 tanks of the 105th Armored Brigade, the better part of another tank regiment appears to have been available to North Korea in late June. Thirty tanks reportedly joined the N.K. 7th (12th) Division at Inje in east central Korea just before it crossed the Parallel. This gave North Korea a total of 150 Russian-built T34 tanks in June 1950.

In the six months before the invasion, a defensive-type army of 4 divisions and an armored regiment had doubled in strength to form 7 combat-ready divisions and an armored brigade. And there were in addition 3 other newly activated and trained divisions, and 2 independent regiments.

The North Korean ground forces—the NKPA and the Border Constabulary— in June 1950 numbered about 135,000 men. This estimated total included 77,838 men in seven assault infantry divisions, 6,000 in the tank brigade, 3,000 in an independent infantry regiment, 2,000 in a motorcycle regiment, 23,000 in three reserve divisions, 18,600 in the Border Constabulary, and 5,000 in Army and I and II Corps Headquarters.

The North Korean infantry division at full strength numbered 11,000 men. It was a triangular division composed of three rifle regiments, each regiment having three battalions. [The 12th Division had a strength of 12,000.] The division had as integral parts an artillery regiment and a self-propelled gun battalion.

[NOTE 1-15NKA: The estimate of 135,000 is based on the following tabulation, drawn principally from N.K. PW interrogation reports:

There were also medical, signal, antitank, engineer, and training battalions, and reconnaissance and transport companies. The artillery support of the North Korean division in 1950 closely resembled that of the older type of Soviet division in World War II. A division had 12 122-mm. howitzers, 24 76-mm. guns, 12 SU-76 self-propelled-guns, 12 45-mm. antitank guns, and 36 14.5-mm. antitank rifles. In addition, the regiments and battalions had their own supporting weapons. Each regiment, for instance, had 6 120-mm. mortars, 4 76mm. howitzers, and 6 45-mm. antitank guns. Each battalion had 9 82-mm. mortars, 2 45-mm. antitank guns, and 9 14.5-mm. antitank rifles. The companies had their own 61-mm. mortars. A North Korean rifle regiment at full strength numbered 2,794 men—204 officers, 711 noncommissioned officers, and 1,879 privates.

From the beginning the Soviet Union had been the sponsor for the NKPA and had provided it with the sinews of war. Most important at first were the Russian-built T34 tanks of the 105th Armored Brigade. The T34 was a standard medium tank in the Soviet Army at the end of World War II. The Russians first used this tank against the Germans in July 1941. Guderian gives it the credit for stopping his drive on Tula and Moscow. The T34 weighed 32 tons, was of low silhouette, had a broad tread, and was protected by heavy armor plate. It mounted an 85-mm. gun and carried two 7.62-mm. machine guns, one mounted on the bow and the other coaxially with the gun.

[NOTE 1-19 Not until the end of the third week of the war did American intelligence settle on the identification of the T34 tank.]

Other ordnance items supplied to the NKPA by the Soviets included 76-mm. and 122-mm. howitzers; 122-mm. guns; 76-mm. self-propelled guns; 45-mm. antitank guns; 61-mm., 82-mm., and 120mm. mortars; small arms; ammunition for these weapons; and grenades. From the Soviet Union North Korea also received trucks, jeeps, radios, and fire control, signal, and medical equipment.

In the spring of 1950 the Soviet Union made particularly large shipments of arms and military supplies to North Korea. One captured North Korean supply officer stated that in May 1950, when he went to Chongjin to get supplies for the N.K. 5th Division, Soviet merchant ships were unloading weapons and ammunition, and that trucks crowded the harbor waterfront area. Korean-speaking crew members told him the ships had come from Vladivostok. Markings on some of the North Korean equipment captured in the first few months of the Korean War show that it was manufactured in the Soviet Union in 1949-50 and, accordingly, could not have been matériel left behind in 1948 when the occupation forces withdrew from North Korea, as the Soviets have claimed.


North Korea began the war with about 180 aircraft, all supplied by Russia. Of these about 60 were YAK trainers; 40, YAK fighters; 70, attack bombers; and 10, reconnaissance planes. The North Korean Navy had approximately 16 patrol craft of various types and a few coastwise steamers reportedly equipped with light deck guns.

Army of the Republic of Korea

In June 1950 President Syngman Rhee was Commander in Chief of the South Korean Army. Under him was Sihn Sung Mo, the Minister of National Defense. The Deputy Commander in Chief actually in command of the Army was Major General Chae Byong Duk.

The origins and development of an armed force in South Korea had their roots, as in North Korea, in the occupation period after World War II. At first the principal objects of the U.S. occupation were to secure the surrender of the Japanese troops south of the 38th Parallel, return them to Japan, and preserve law and order until such time as the Koreans could do this for themselves.

In January 1946 a Korean constabulary was authorized and established. This organization took form so slowly that a year later it numbered only 5,000 men. By April 1947, however, it had doubled in strength and by July of that year it had reached 15,000. The constabulary became the Republic of Korea (ROK) Army in August 1948 and grew so rapidly in the next few months that by January 1949 it numbered more than 60,000 men. In March 1949 the Republic of Korea had an Army of 65,000, a Coast Guard of 4,000, and a police force of 45,000—a total security force of about 114,000 men. The United States had equipped about 50,000 men in the Army with standard infantry-type weapons and matériel, including the M1 rifle and 60-mm. and 81-mm. mortars.

Upon withdrawal of the last of the U.S. occupation force at the end of June 1949 a group of 482 United States military advisers began working with the South Korean Army. This small group of U.S. Army officers and enlisted men, established on 1 July 1949 with an authorized strength of 500 men, was called the United States Korean Military Advisory Group to the Republic of Korea (KMAG). Its mission was “to advise the government of the Republic of Korea in the continued development of the Security Forces of that government.” KMAG was an integral part of the American Mission in Korea (AMIK) and, as such, came under the control of Ambassador Muccio. In matters purely military, however, it was authorized to report directly to the Department of the Army and, after co-ordinating with Ambassador Muccio, to inform General MacArthur, the Commander in Chief, Far East (CINCFE), of military matters.

In April 1950 the South Korean Government began the formation of combat police battalions to relieve the Army of internal security missions, but of twenty-one battalions planned only one, that activated at Yongwol on 10 April 1950 to provide protection for the power plant, coal mines, and other vital resources in that vicinity, was in existence when the war started.

[NOTE 1-25ROK: Rpt, USMAG to ROK, 1 Jan-15 Jun 50, Annex I. The Department of the Army in a message to General MacArthur dated 10 June 1949 established KMAG. It became operational in Korea on 1 July 1949. Msg, G-3 Plans and Opns to CINCFE WARX90049, 10 Jun 49. The KMAG personnel present for duty 1 July 1949 numbered 482: 165 officers, 4 warrant officers, and 313 enlisted men. Sawyer, KMAG MS; Msg, WX90992, DA to CG USAFIK, 2 Jul 49, cited in General Headquarters Support and Participation, 25 June 1950-30 April 1951, by Major James F. Schnabel (hereafter cited as Schnabel, FEC, GHQ Support and Participation in Korean War), ch. I, pp. 4-5. This is Volume I of Far East Command, United Nations Command, History of the Korean War, in OCMH.]

By June 1950 the Republic of Korea armed forces consisted of the following: Army, 94,808; Coast Guard, 6,145; Air Force, 1,865; National Police, 48,273. When the war began nearly a month later the Army had a strength of about 98,000, composed of approximately 65,000 combat troops and 33,000 headquarters and service troops.

NOTE 1-2626 Schnabel, FEC, GHQ Support and anticipation in Korean War, sec. V, p. 16; Interv, author with Major James W. Hausman, 12 Jan 52. Major Hausman was KMAG adviser to the ROK Army Chief of Staff in June 1950. KMAG figures for 1 June give a total of about 67,000 in the eight infantry divisions]

In June 1950 the combat troops of the ROK Army were organized into eight divisions: the 1st, 2nd, 3rd, 5th, 6th, 7th, 8th, and Capital Divisions. Five of them, the 1st, 2nd, 6th, 7th, and Capital, had 3 regiments; two divisions, the 3rd and 8th, had 2 regiments; and one division, the 5th, had 2 regiments and 1 battalion. Only four divisions, the 1st, 6th, 7th, and Capital, were near full strength of 10,000 men.

The organization of the combat divisions and their present-for-duty strength are shown in Table 1. For some unknown reason the ROK Army headquarters report, on which Table 1 is based, does not include the 17th Regiment. It numbered about 2,500 men and was part of the Capital Division in the paper organization of the Army.

[NOTE 1-27G3: Interv, author with Major General Chang Chang Kuk (Military Attaché, Korean Embassy, Washington), 14 Oct 53. General Chang was G-3 of the ROK Army in June 1950. Rpt, USMAG to ROK, 1 Jan15 Jun 50, Annex IX. Major Hausman says he always considered 10,000 as the table of organization strength of a South Korean division. Some references give the figure as 9,500. General Chang said the ROK Army considered 9,000-9,500 as T/O strength of a division in June 1950. Spelling of names and rank as of June 1950 checked and corrected by General Chang and by General Paik Sun Yup, ROK Chief of Staff, in MS review comments, 11 July 1958. In accordance with Korean usage, the surnames come first, the name Syngman Rhee is one of the rare exceptions to this rule. Korean personal names ordinarily consist of three monosyllables.

In the early summer of 1950 the 1st, 7th, 6th, and 8th Divisions, considered the best in the ROK Army, held positions along the Parallel in the order named, from west to east. Beyond the 1st Division at the extreme western end of the line was the 17th Regiment of the Capital Division on the Ongjin Peninsula. The other four divisions were scattered about the interior and southern parts of the country, three of them engaged in anti-guerrilla activity and training in small unit tactics. The Capital Division’s headquarters was at Seoul, the 2nd’s at Ch’ongju near Taejon, the 3rd’s at Taegu, and the 5th’s at Kwangju in southwest Korea.

The South Korean divisions along the Parallel were equipped mostly with the United States M1 rifle, .30-caliber carbine, 60-mm. and 81-mm. mortars, 2.36 in. rocket launchers, 37-mm. antitank guns, and 105-mm. howitzers M3. The howitzers had been used in the U.S. infantry cannon companies in World War II. They had a shorter barrel than the regular 105-mm. howitzer M2, possessed no armor shield, and had an effective range of only 7,250 yards (8,200 yards maximum range) as compared to 12,500 yards for the 105-mm. howitzer M2.

There were five battalions of these howitzers organized into the usual headquarters and service companies and three firing batteries of five howitzers each. The 1st, 2nd, 6th, 7th, and 8th Divisions each had a battalion of the howitzers. A sixth battalion was being formed when the war started. Of 91 howitzers on hand 15 June 1950, 89 were serviceable.

The South Korean armed forces had no tanks, no medium artillery, no 4.2-in. mortars, no recoilless rifles, and no fighter aircraft or bombers. The divisions engaged in fighting guerrillas in the eastern and southern mountains had a miscellany of small arms, including many Japanese Model 99 World War II rifles.

In October of 1949 the ROK Minister of Defense had requested 189 M26 tanks but the acting chief of KMAG told him the KMAG staff held the view that the Korean terrain and the condition of roads and bridges would not lend themselves to efficient tank operations. About the same time a KMAG officer pointed out to Ambassador Muccio that the equipment provided the ROK’s was not adequate to maintain the border, and he cited the fact that North Korean artillery outranged by several thousand yards the ROK 105-mm. howitzer M3 and shelled ROK positions at will while being out of range of retaliatory fire.

The ROK Army in June 1950 had among its heavier weapons 27 armored cars; something more than 700 artillery pieces and mortars, including 105-mm. howitzers and 81-mm. and 60-mm. mortars; about 140 antitank guns; and approximately 1,900 2.36-in. bazookas. In June 1950 it had about 2,100 serviceable U.S. Army motor vehicles for transportation, divided between about 830 2-1/2 ton trucks and 1,300 ¼-ton trucks (jeeps). Motor maintenance was of a low order.

[NOTE 1-30ROK: The original U.S. commitment in July 1949 was to supply the Korean Army with an issue of equipment and a six months’ supply of spare parts for a force of 50,000. See Memo, Gen Roberts to All Advisers, KMAG, 5 May 50, sub: Korean Army Logistical Situation. The Department of State gives $57,000,000 as the value of military equipment given to South Korea before its invasion by North Korea,with a replacement cost at time of delivery to South Korea of $110,000,000. See The Conflict in Korea, p. 10.]

The South Korean Air Force in June 1950 consisted of a single flight group of 12 liaison-type aircraft and 10 advance trainers (AT6). Major Dean E. Hess, KMAG adviser to the South Korean Air Force, had a few (approximately 10) old F-51 (Mustang) planes under his control but no South Korean pilots had yet qualified to fly combat missions. These planes were given to the ROK Air Force on 26 June 1950.

On 25 June the South Korean Navy consisted of a patrol craft (PC701) recently purchased in the United States from surplus vessels, 3 other similar patrol craft at Hawaii en route to Korea, 1 LST, 15 former U.S. mine sweepers, 10 former Japanese mine layers, and various other small craft.

In June 1950 the ROK Army supply of artillery and mortar ammunition on hand was small and would be exhausted by a few days of combat. An estimated 15 percent of the weapons and 35 percent of the vehicles in the ROK Army were unserviceable. The six months’ supply of spare parts originally provided by the United States was exhausted.

The state of training of the ROK

Army is reflected in the Chief of KMAG’s report that a majority of the units of the South Korean Army had completed small unit training at company level and were engaged in battalion training.

In summary, the North Korean Army in June 1950 was clearly superior to the South Korean in several respects: the North Koreans had 150 excellent medium tanks mounting 85-mm. guns, the South Koreans had no tanks; the North Koreans had three types of artillery—the 122-mm. howitzer, the 76-mm. self-propelled gun, and the 76-mm. divisional gun with a maximum range of more than 14,000 yards which greatly outranged the 105-mm. howitzer M3 of the ROK Army with its maximum range of about 8,200 yards. In number of divisional artillery pieces, the North Koreans exceeded the South Korean on an average of three to one. The North Koreans had a small tactical air force, the South Koreans had none. In the North Korean assault formations there were 89,000 combat troops as against approximately 65,000 in the South Korean divisions. Also, North Korea had an additional 18,600 trained troops in its Border Constabulary and 23,000 partially trained troops in three reserve divisions. In comparison, South Korea had about 45,000 national police, but they were not trained or armed for tactical use. The small coast guard or navy of each side just about canceled each other and were relatively unimportant

[NOTE 1-33ART: The maximum range of the Soviet artillery used by the N.K. Army in June 1950 was as follows: 122-mm. howitzer, 12,904 yards; 76-mm. SP gun, 12,400 yards; 76-mm. divisional gun, 14,545 yards. The average North Korean division had 48 122-mm. howitzers, 76-mm. SP and non-SP guns; the ROK division had 15 105-mm. howitzers M3.]

The superiority of the North Korean Army over the South Korean in these several respects was not generally recognized, however, by United States military authorities before the invasion. In fact, there was the general feeling, apparently shared by Brigadier General William L. Roberts, Chief of KMAG, on the eve of invasion that if attacked from North Korea the ROK Army would have no trouble in repelling the invaders.

SOURCE: South to the Naktong, North to the Yalu; BY: Colonel Roy E. Appleman (United States Army Center of Military History)

Korean War: Invasion Across the Parallel (3)

Korean War: (1) Background to Conflict


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