on the afternoon of march 25, at the battle of jones's farm, union forces of ii corps and vi corps (sixth corps) captured confederate picket lines near armstrong's mill and extended the left end of the union line about closer to the confederate fortifications. this put the vi corps which was holding this section of the line, within easy striking distance, about , of the confederate line. after the confederate defeats at fort stedman and jones's farm, lee knew that grant would soon move against the only remaining confederate supply lines to petersburg, the southside railroad and the boydton plank road and possibly cut off all routes of retreat from richmond and petersburg.