Battle
Stop retreating, supply the sectors, prevent the breaches from joining
Military history
The Busan Perimeter was neither a single set-piece battle nor an airtight line. In July, American and South Korean forces traded space for time; in early August, Walker ended the retreat and ordered a compressed arc around the last major port to be held. The Korean People's Army then sought several breaches before its logistical distances, losses, and arriving reinforcements reduced its momentum. The defence combined Busan's railways and port, interior lines, artillery, air support, and reserves shifted toward failing sectors. The account follows this mechanism without turning the Incheon landing into a retrospective explanation for every fight around the perimeter.
In early August, Walker abandoned the withdrawal strategy that had bought time in July and ordered a final redoubt. The defensive arc, irregular rather than continuous, rested chiefly on the Nakdong and Nam in the west and southwest, then on high ground toward the east coast. Busan provided the port, railway, and roads; Taegu, Miryang, and the Naktong crossings organised the interior lines.
The UN/ROK deployment linked American and South Korean sectors rather than forming an airtight barrier: the 25th, 24th and then 2nd Divisions, and 1st Cavalry Division covered the southwest, Nakdong, and Taegu, while ROK forces held the eastern arc. KPA I and II Corps attacked from west, north, and east; a local gain still had to become an operational breakthrough.
Aircraft, artillery, and naval fire made no sector invulnerable, but slowed columns and bought time to land reinforcements. The 1st Provisional Marine Brigade, 5th Regimental Combat Team, 2nd Division, and tanks were committed as crises arose; the KPA had to sustain attacks ever farther from its bases.
The August offensives and the Great Offensive of 31 August created real penetrations west of Taegu, at the Nakdong, near Masan, and toward Pohang. The defence contained these bottlenecks without eliminating every threat; Walker even moved his headquarters from Taegu to Busan on 5 September. Incheon, off this map, on 15 September and the attack on the 16th then accelerated the withdrawal without erasing the earlier fighting.
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Military history
CMH Pub 20-2, chap. XV, « Establishing the Pusan Perimeter », pp. 252–256; chap. XXIV, « The Great Naktong Offensive », pp. 460–487; chap. XXVII, « Breaking the Cordon », pp. 542–548.
Perimeter, geography, units, reserves, early-September crises, maps of the axes, supply effects, and the breakout attack on 16 September.
View ↗Sections « The Pusan Perimeter » et « The Breakout », lignes web 73–80 (périmètre et Task Force Kean), 84–90 (Taegu, offensive du 31 août et renforts), 92–98 (Incheon le 15 septembre et sortie du 16 septembre).
Short chronology, Busan's functions, Walker's reorganisations, threats to Taegu/Masan/Pohang, and the Incheon–breakout hinge.
View ↗PDF, pp. 17–18: carte « The Pusan Perimeter 1 August–1 September 1950 » et quatre avenues d’avance; pp. 18–20: Task Force Kean (ordre du 6 août, attaque du 7), Naktong Bulge, P’ohang/Kyongju/Yonil et Taegu; pp. 21–23: défense du Naktong du 1er au 15 septembre, déplacement du QG de Walker, 2e/25e divisions et contexte de la sortie (locators web P17–P23, lignes 596–655, 665–701, 702–744, 754–867).
Official topography, order of battle by sector, four approaches, Task Force Kean/Naktong/Pohang/Taegu sequence, contrasting orders of magnitude, and September defence.
View ↗Vol. I, pp. 240–241, passage sur la 1st Provisional Marine Brigade, le premier pont KPA sur le Naktong, la reprise d’Obong-ni et le retrait des Marines le 5 septembre; édition HTML, lignes 1131–1138 (forme du périmètre et logistique) et 2633–2657 (Task Force Kean, contre-attaque et résultat).
Role of the Marines and counterattacks at the Naktong, limits of a bridgehead, and cost of halting the offensive.
View ↗Brochure PDF, p. 1, lignes 1–22: dates 4 août–18 septembre, ordre de grandeur 140 000 ONU/ROK contre 98 000 KPA et secteurs Daegu/Masan/Pohang/Nakdong; lignes 23–29: brigade provisoire de Marines réactivée le 7 juillet, arrivée à Pusan le 3 août et subordination à Walker.
Operational bounds, role of the port, institutional synthesis of sectors, and an order of magnitude explicitly presented as indicative.
View ↗Conseil de sécurité, document S/1801, 18 septembre 1950, 23 p.; p. 1 et releases 438–449, datés des 15–16 septembre, transmis au Secrétaire général avec les communiqués contemporains du Commander-in-Chief UN Command.
Contemporary cross-check of the front situation at the date of the breakout and documentary endpoint of 18 September; communiqués are treated as situated reports, not neutral measurements of losses.
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