To help preserve this tactical surprise, the plan for the Bunker Hill attack included a diversionary attack against Siberia. Making this secondary effort would be a reinforced rifle platoon and a composite unit of gun and flame tanks. For the main attack, Lieutenant Colonel Batterton’s 2d Battalion would employ a reinforced rifle company with supporting artillery and armor, if needed. The operation was to be conducted at night, to further ensure the opportunity for tactical surprise. For the same reason, the attack was not to be preceded by artillery preparation on either objective. To the right of the 1st Marines, however, Colonel Culhane’s 5th Marines would support the diversion by artillery and tank fire placed on enemy strongpoints in the Ungok area, about 1¼ miles northeast of Siberia. During daylight, air, artillery, and tanks attacked targets on both 122 and 58A. Priority of effort in the 1st Marines area went to units preparing for the Siberia-Bunker offensive. _The Attack on Bunker Hill_[178] [178] Unless otherwise noted, the material for this section is derived from: Encl (1) to CG, FMFPac ltr 0762/161 over A9 to CMC, dtd 25 Nov 52, Subj: “Summary of 1stMarDiv Sit from 20 July-20 Oct 52,” hereafter FMFPac, _1stMarDiv Sum, Jul-Oct 52_; 1stMarDiv, 1stMar, 2/1, 1st TkBn ComdDs, Aug 52. At dusk on 11 August, 1,000 yards behind the MLR in the western sector of the 2/1 line, the eight Company C tanks that were to provide much of the diversionary effort at Hill 58A moved out of their assembly area. Leading the column east of the MSR, Changdan Road, were four M-46 mediums, mounting 90mm guns. They were followed by an equal number of flame vehicles. Each M-46 was specially equipped with an 18-inch fighting light, actually a searchlight with a shutter over the lens, to be used for battlefield illumination. The flame vehicles, World War II M4A3E8 mediums, mounted a 105mm howitzer in addition to the flame tube. As the tanks reached the Changdan Road, they turned north, crossed the MLR, and proceeded to preselected positions. (See Map 10.) [Illustration: MAP 10 K. WHITE 2/1 SECTOR 9–11 AUGUST 1952]