Attaching to the opponent's centre line or head/neck are two prime areas for indexing.
I'm currently working on the draft of the upcoming second volume of my Seed of Shuri Karate book series and I thought that followers of my work may enjoy this little segment taken from the chapter on percussive impact delivery. The finished publication will no doubt read different to this as I always extensively edit, but nevertheless, I hope you'll find this sneak peek on the principle of 'indexing' a nice complement to your cup of coffee...
Indexing (also known as a 'set up', 'controlling', gauge' or 'leveraging arm') is an important concept taught in modern day self-defence systems and is also a key tactic expressed throughout the application of classical movements found in karate kata. You only need to spend a few moments searching YouTube for footage of real street attacks, self-defence encounters or bar brawls and you will see that the use of indexing is rife. This is simply due to the fact that it is both natural and highly advantageous. It is also a strategy used extensively in weapon attacks (especially puncture weapons such as knives or screwdrivers), where repetitive thrusting or clubbing 'sewing machine' styles are employed to devastating effect.