What is 6 TECHNIQUE?
6 TECHNIQUE meaning position where defensive lineman is located before the snap. In the original Bum Phillips’ version (See definition of 0 technique above) of this terminology, a 6 technique was nose-to-nose with the offensive tight end. Some coaches make slight, but important-to-understand, changes while seemingly using the same terminology. For example, at Monte Vista High School in Danville, CA where I coached from 2003 to 2005, a 6 technique meant that the nose of the defensive lineman was on the outside shoulder of the offensive tackle.
reference: John T. Reed: DICTIONARY OF AMERICAN FOOTBALL TERMS