A zero technique is when the defensive tackle is aligned nose to nose with the offensive center, basically right down the middle of the center, not shaded to a shoulder. In the 46' defensive tape I have, Rex devotes 5 minutes of instruction called "playing the zero technique." I have always referred to a 1 technique as playing on the shoulder of the offensive center.
I agree, this has went on long enough. This is a Cardinal board, but I will offer one final explanation. The key characteristic of the "46" defense is that the center and both guards are covered by defensive lineman. A zero technique on the center and two defensive lineman aligned on the outside shoulder of both guards. This creates one-on-one blocking for the center,therefore in most "46" defenses they align their best lineman on the center. Swann in 94 and 95, White with the Eagles, and Hampton in Chicago. Against many formations the "46" will have 5 men on the LOS and two LB"s ,therefore appearing to be a 3-4, but in most 3-4's (Dallas, New England, and Pittsburgh) their tackles almost always align on the offensive tackles. In the "46" they cover up the guards. If there is a TE , Reed drops out of the sky to become the eigth man. In 3 and 4 wideout looks the "46" will have 7 in the box and appear to be a 3-4, but both guards and center are covered. Against a Pro Set, it is an 8 man front, against double tights they stack 7 on the LOS. It is an extremely complex defense and changes looks according to offensive formation. The one signature is the three DL covering the center and both guards. Against tight or run formations REED becomes the eighth man.
I will watch Baltimore closely the rest of the season to see what they are doing defensively. Rex Ryan is a brilliant coordinator, that is extremely unconventinal. He plays some 3-4, 4-3, "46", and some things I am not sure of. I would love to hear their defensive huddle because they present some unique fronts and coverages.
If, as you say, they are playing a majority of 3-4 I haven't seen it, and am somewhat shocked considering the NFL network did an hour long show with Sam Huff and Ray Lewis where Lewis spent the majority of the time bashing the 3-4. They later interviewed Buddy and Huff and they both said the 4-3 was the best defense to run.Rex has been a base 4-3 coach his entire career, but maybe he is beginning to branch off. Enjoyed the discussion.