Hello Martin!
The Motherline is the line that runs through your body, from the very center of the top of your head right down to, well, you know!

When you face an opponent, it is the Motherline that determines your alignment on them (based on Theory of Facing). You can not always face the opponent's centerline, but you can always line up on their motherline.
The Centerline is the actual line running down the front of the body where the vital targets are located. You should attempt to attack the opponent's centerline while protecting your own.
I hope that clears it up for you! I am looking forward to seeing you and Phil in June! We will have a great time! Take care and God Bless!
Keep Blasting!
Sifu Lamar M. Davis II
Senior Instructor
Hardcore Jeet Kune Do
Sifu@HardcoreJKD.com
JKD@windstream.net
http://www.HardcoreJKD.com
Phone (205) 296-7070 (Incoming Only)
"Hit Hard, Hit Fast, Hit First - ALWAYS!"
"The REAL future of Jeet Kune Do belongs to US, the few, the proud, the HARDCORE! Now, what are we going to do with it?" _ Sifu Lamar M. Davis II