The Abucay- Morong Line, First Major Defense Line of the USAFFE on Bataan crossed at this point deployed from right (East) to (West) where the 57th Regiment Combat Team Philippine Scouts 41st Div. Phil. Army Brig. Gen. Vicente Lim (PA) 51st Div. Phil. Army Brig. Gen. Clifford Bluemel (AUS) and the 1st Regular Div. Phil. Army Brig. Gen. Fidel V. Segundo, PA, first major engagement of this line, 12 January 1942, to the west of the road near the limiting point of the 57th RCT and the 41st Div. Falling to crush through the  enemy shifted farther west and attacked the center of the 41st Division, 17 January, 1942, then the limiting point of the 51st Div. 20 January 1942. Left flank of the 1st Regular Div. Along the axis of the Morong-Bagac Road, also assaulted 20 January 1942 enemy infiltration through unmanned portion of the line between Mount Natib and Silanganan resulted in the envelopment of the 1st Regular Div. and finally the abandonment of the Pilar-Bagac Line on 24 January, 1942.