The three major lines are the two induvidual lines - The Core line and the Center line, and the mutual Attacking line.
The core line must be vertical to ensure the 7 Joints are aligned.
The center line Line of Gravity must be at the attacking line aiming towards the opponents Core Line in order to maintain own frontality,
and to destroy opponents frontality when splitting arms around Line of Gravity
into a squared position with one DAR arm
and one WU arm (1.M.Y.C),
either Closing or Splitting (Closers/Splitters).