In early June the recently appointed UN commander, General Clark, made his first visit to the 1st Marine Division front. During his briefing, General Selden reviewed the unusual combat difficulties confronting his Marines. In addition to the unfavorable terrain, the division commander noted the special operational restrictions caused by proximity to the truce talk site. Presence of a large number of uncharted minefields created another obstacle. Herculean efforts were required of the Marines to simultaneously man and construct defenses over 35 miles of JAMESTOWN. Adding to Marine problems were the facts that ground units were not receiving sufficient close air support and the capabilities of the Chinese were constantly increasing.
Chinese order of battle (OOB) information was fed into the division intelligence network by higher commands, I Corps and EUSAK, and adjacent units, but a large part of the data about Communist forces was produced by the division itself. Frontline units in contact with the enemy, by observation of his activities, supplied the bulk of intelligence about enemy defense tactics, employment of weapons, and combat characteristics. Supporting Marine division units, particularly artillery and armor, fed more facts into the system, mostly through identification of the caliber of enemy shells fired at the Marines. As a result of its missions forward of the line and actions in defense of it, the division reconnaissance company also contributed to the intelligence network. Individual Marines, performing as tactical air observers and artillery air observers, as well as the VMO and HMR pilots, were other important sources readily available to the 1st Marine Division.
G-2 directed the division intelligence effort, including processing of raw material and supplying of updated reports to 1st Division units. The G-2 section also maintained OOB and target identification data on Chinese units and their commanders. Members of the G-2 staff also assisted in interrogation of prisoners of war (POWs), screened the civilians apprehended in unauthorized areas, debriefed Marines exposed to enemy intelligence, and conducted inspections of division internal security. In areas where the 1st Marine Division had only a limited intelligence capability it turned to EUSAK for assistance.
Eighth Army teams augmented the division counterintelligence efforts and provided most of the translation service. In addition, three radio intercept units furnished information to the Marines. The critical importance of this service had been proven during several combat patrols in May when additional information was instantly radioed to a friendly unit under fire.
Other intelligence activities were less beneficial to the Marines. These operations were conducted by Tactical Liaison Officers (TLOs, friendly Koreans trained by U.S. intelligence teams), and members of a Higher Intelligence Detachment (HID), a Korean unit assigned from EUSAK. Both the TLO and HID proved of limited value to the division, due to the generally poor educational background of the agents, their inadequate training, and frequent failure to return from assignments behind enemy lines. Some Marines believed the basic fault in these operatives lay in “an exaggerated opinion of their importance.”[134]
[134] PacFlt EvalRpt No. 4, p. 9-33.
Several division intelligence Marines, in conjunction with training and shore party personnel, took part in an informational activity of a different type. These Marines reconnoitered several friendly islands off western Korea to determine their suitability for division landing exercises. The second one inspected, Tokchok-to, 30 miles southwest of Inchon, was selected. By early June planning had progressed to the point where a program had been developed for bimonthly battalion landing team exercises. The KPR maneuver force, appropriately reinforced, was designated as a participating unit. Landings were to employ boat teams, amphibian tractors, and helicopters. The entire program was designed to provide refresher training for Marines in carrying out their primary mission of amphibious assault. By the end of June, 3/5 and 3/1, in turn, had captured Tokchok-to.
Other training concentrated more on the task at hand. Division units in reserve rehearsed tactics for offensive and defensive warfare. Most ground units conducted extensive schooling in both mine and booby trap detection and clearance. Recognizing that patrolling was an important part of a Marine’s life on the MLR, the division included in its Noncommissioned Officers’ (NCO) Leadership School a thorough indoctrination in patrolling tactics.[135] More than 50 percent of the training at all levels was at night. In addition, an extensive orientation was conducted for newly arrived combat replacements, who could not be committed to action for 72 hours after joining the division.
[135] BGen Austin R. Brunelli ltr to Hd, HistBr, G-3 Div, HQMC, dtd 13 Sep 66, hereafter Brunelli ltr. The division chief of staff during more than half of 1952, Colonel Brunelli later observed that the “school produced more effective patrolling and ... contributed to reducing our casualties.”
A week after the division’s June replacements landed at Inchon, General Selden’s headquarters received a directive that would affect a number of these new Marines. On 10 June CG, EUSAK ordered his corps commanders to make continuous efforts to secure the identification and changes in the enemy order of battle. Two days later I Corps followed the Eighth Army order with a letter of instruction which called for each I Corps division to “prepare plans for launching swift, vigorous, and violent large-scale raids to capture prisoners, to gain intelligence, to destroy enemy positions and material and/or strong limited objective attacks to improve and strengthen Line JAMESTOWN.”[136] Large scale was defined as an “attacking force limited to battalion or regimental (brigade) size with appropriate armor and artillery support.”[137] Divisions were required to submit detailed proposals for future action by 21 June. Marine division plans for limited objective attacks during July by units of the 7th Marines and KMCs were subsequently prepared and forwarded to I Corps.