As the morning passed , General Walker decided that the situation was most critical in the Naktong Bulge area of the US 2nd Division sector . There the North Koreans threatened Miryang and with it the entire Eighth Army position . At 11 : 00 Walker ordered US Marine Corps Brigadier General Edward A. Craig , commanding the 1st Provisional Marine Brigade , to prepare the marines to move at once . The marines made ready to depart for the Naktong Bulge at 13 : 30 .