Army planning had been initiated by the Joint Strategic Plans and Operations Group until 16 August, when the “Special Planning Staff” was set up at GHQ to issue directives for Operation Plan CHROMITE. Published on 12 August as CinCFE Operation Plan No. 100-B, it was based on these assumptions: (a) that the North Korean ground advance would be stopped in time to permit the build-up of our forces in South Korea; (b) that our forces in South Korea would be built up to the capability of mounting effective offensive operations against NKPA forces opposing them; (c) that we retain air and naval supremacy in the area of operation; (d) that the NKPA ground forces would not receive major reinforcements from the USSR or Red China; (e) that there would be no major change in the basic disposition of the NKPA forces.[89] [89] MarCorps Board _Study_, v. II-B, 13–17. It was understood from the beginning that the Special Plans Staff, headed by General Ruffner, would be the nucleus of the future X Corps staff. In order to have the benefit of specialized amphibious knowledge, ten Marine and two Navy officers of TTU Mobile Training Team Able were assigned on 19 August: Col H. A. Forney Deputy Chief of Staff LtCol J. Tabor Asst Coordinator, FSCC LtCol C. E. Warren Asst G-4 Maj J. N. McLaughlin Asst G-3 Maj J. F. Warner Asst G-3 Maj C. P. Weiland Air Officer, FSCC Maj V. H. Vogel Asst G-4 Capt H. S. Coppedge Asst G-2 Capt T. A. Manion Asst Signal Officer, FSCC Capt V. J. Robinson Target Info Officer Lt L. N. Lay, USN Asst Surgeon Lt W. A. Sheltren, USN Asst NGF Officer, FSCC[90] [90] MarCorps Board _Study_, v. II, app. 67. These officers did not begin their new assignment in time to contribute to the preliminary X Corps over-all scheme of maneuver. The main provisions, as communicated to General Smith at General Ruffner’s briefing conference of 23 August, were as follows: (1) The 1st Marine Division, as the landing force, was to seize the urban area of Inchon (line A-A); to capture a beachhead (line B-B); to advance as rapidly as possible and seize Kimpo Airfield (line C-C); to clear out the south bank of the Han River (line D-D); to cross the river, seize Seoul and secure the commanding ground to the north (E-E); and, finally, to fortify and occupy this line with reduced forces until relieved (apparently by the 3d Infantry Division, still in the United States), whereupon the Division was to recross the Han and seize a line (F-F) about 25 miles southeast of Seoul.