Blocking Rules

I am not sure what you are asking for. What rules are you looking for, in regards to what scheme.
HosHos

The Question you need to ask your self is where you are prepared to have an unblocked man? to the Outside? Then you might want to use a rule that starts 1st with backside Gap like BS Gap, On-Downman, Off- Lber, Middle- if no one in either of these 3 places get across the middle on the 2nd level . If you are leading with a back off the edge this is a pretty good base rule too. (that was our old Rule) Now we are more of a zone team and when in doubt we call Bucket. We take a step back and open our shoulders on about a 45degree angle and block what ever crosses our path. This is good for a stacking stunting defense or unorthodox defenses. The weakness is that the unblocked is usually the backside edge players.

When in doubt, hit the closest guy to you.

If you are confused and will get the assignment wrong, block the most dangerous man.

That may be too simplistic, but can help.

Bigcat

As I understand the history:

Assignment blocking came first ( c blk 0, g block #1, T on #2, TE on #3 etc)
this was good vs old head up alignments.

Then "Rule" blocking such as scan from inside: gap(usually called inside), on, lb. This was ok vs gap defenses.

Those were 'default' style rules- what you did if you didnt know what else to do, but sometime also the only rule for a number of plays in a simple offense..

then more complicated teams combined "rule" with "assignment" styles. The rules often needing seperate sets of rules for odd or even defenses, or even worse for each "front" So that a rule might read "c block man on, if 'even' block back, 'even' with a MLB block back & call fold", G block #1, T block #2 if on LOS else Double team down on #1, vs split-6 chip off Def tackle to lb inside" etc.

As defenses became gap-control, slanting, and "crosscharging" the first two styles while "simplest" and in some ways therefore 'best' now became almost worthless, as bad as giving them a rule such as "hit somone, as long as you hit hard" - a formula for lost yards.

With crosscharging even the detailed third style above becomes obsolete in addition to a severe recipe for "I was confused so I hit someone" because fronts are often no longer identifiable, offensive formations become multiple forcing some assignment variations and playbooks often become enlarged.

Therefor the advent of 'Area' blocking and then 'Zone' blocking. both of which protect from having to guess what stacks and stunts are going to do in advance but rather adjust on the fly.

The more recent 'Zone' style attempts to get double teams on all down defenders and then have one blocker come off on the LB when he commits and arives.

At a simpler level is what I think of as Area blocking which does one of two things:
1. Most everyone blocks to backside area "down" while some back or backside lineman kicks out frontside.
2. Most everyone "T-steps" or "L-steps" foward and out to playside and runs thru their playside gap picking up any stunting or 'color' which shows on their way to 2nd or 3rd level. This is principally a "man"
scheme as opposed to the double-to-backer approach of the Zone style.

This past season we applied the 'area' style to most plays for most positions and it works very well with no "rules" to drill and remember. If we had a running play rule book it would have said: "on power and counter -other than the pullers everyone blocks down" All other run plays step playside and block what shows. Each play might have a one or two man speciality ie X-block on belly, part the sea on isol. etc. while the rest of the line stepped playside. I never actually used the word "rule" with the linemen.

The zone style is designed to fit with the backs delayed arrival at the line and times up with the lineman's delayed release to the 2nd level that is when the stack has broken and the crosscharge is revealed. This style therefore fits only with specific designed plays while 'area' can apply in general.