When writing the history of the National Football League there are any number of trends, shifts, strategies and alignments, on both offense and defense, that warrant mention when the subject turns to the game itself.

One-platoon football. The T. Man in motion. Two-platoon football. The Eagle defense. The shotgun. The Flex. Nickel defense. West Coast offense. The zone blitz.

The list is long.

And if there is one play – not a philosophy, not a formation; just one basic play – that begs to be part of the conversation it would be Vince Lombardi's power sweep.

Go all the way back to the days of the flying wedge and the birth of the game in the 19th century and there is no more famous play in football.

With Jerry Kramer on the doorstep of being elected to the Pro Football Hall of Fame, his role in the signature play of the only team that has ever won five NFL championships in a single decade and three straight under a playoff format should jump off his resume.

The two pulling guards with the left halfback in their hip pocket were the focal point of Lombardi's power sweep.

That's not to say others played a lesser part in it. The tight end's block might have dictated the success of the play more than any other. The center, left tackle and fullback certainly had difficult blocks.

But when the play unfolded, the pulling guards were like lead sled dogs piloting the pack.

The Packers could run their power sweep to the left, but they usually ran it right and Kramer's assignment was to pull to the outside of the tight end and block the first man he saw, usually the cornerback. Because the tight end in the power sweep lined up nine feet outside the right tackle, Kramer often escorted the ball carrier to the edge of the play and then had to execute an inside-out block in space.

Other than when he was injured for part of 1961 and most of 1964, Kramer was the starting right guard on Lombardi's nine teams. Until Gale Gillingham replaced him in Lombardi's final season, Fuzzy Thurston was usually the left guard.

While Thurston was a spirited competitor, Kramer was the bigger, stronger, faster guard and almost perfectly sculpted, at 6-foot-3 and 245 pounds, for Lombardi's bedrock play.

Together, it was the two guards who set off alarm bells when defenders saw them coming.

There was "nothing spectacular" about the play, it was "just a yard gainer," Lombardi wrote in his book, "Vince Lombardi on Football."

"But on that sideline," he continued, "when the sweep starts to develop, you can hear those linebackers and defensive backs yelling, 'Sweep! Sweep!' and almost see their eyes pop as those guards turn upfield after them."

Not only was Lombardi's power sweep arguably the most famous play in football history, it also was one that required maximum precision in a sport where execution is pretty much the be-all and end-all of all plays.

Hall of Fame coach John Madden often told the story about how he went to a coaching clinic in Reno, Nev., signed up for Lombardi's lecture, titled "The Green Bay Sweep," and was mesmerized for eight hours.

"He stood up there at the blackboard with a piece of chalk and dissected the Green Bay sweep player-by-player – each player's assignment against every possible defense, against every possible stunt, against every possible blitz, against every possible coverage," said Madden.

Coaches and players who were part of the 1960s Packers will tell you Lombardi never spoke anywhere near that long about his power sweep when he installed it in training camp.

There, he could cover it in 20 to 30 minutes.

But he was unforgiving about the execution of it on the practice field and in film sessions, although, in truth, he was that way about every play.

Lombardi also made it clear that the power sweep was the cornerstone of his offense.

"Every football team eventually arrives at a lead play," he wrote in his two-volume set on the technical aspects of football. "It becomes the team's bread-and-butter play, the top priority play. It is the play the team knows it must make go, and the one the opponents know they must stop."

"My No. 1 play," he added, "has been the power sweep, sometimes called the Lombardi sweep."

While the Packers could run the play against any defense, the use of it was still dictated by defensive alignments, the strengths and weaknesses of the other's teem personnel, and all the other nuances that went into preparing a game plan.

Yes, it was a go-to play. But it was more than that.

It wasn't necessarily a play that the Packers ran repeatedly each and every game, it was more like a trump card, where they forced their opponents to overplay it and leave themselves vulnerable everywhere else. In other words, it was the one play in the Packers' arsenal that set all the others up for success.

"There were play-action passes off it," said Zeke Bratkowski, Bart Starr's backup during Lombardi's final five seasons in Green Bay. "We could trap weak or strong. We could fake to (Jim) Taylor and throw to (Paul) Hornung, fake to Hornung and throw to Taylor. We could screen off that formation. Our drop-back passing game was off that. The weak-side sweep. The halfback option. The sucker play.

"There were so many things we could do, you couldn't zero in."

That's why Kramer's role in the power sweep is such a significant part of his resume and, no doubt, had a lot to do with him being chosen as the only guard on the NFL's 50th anniversary team. He might not have consistently graded the highest on the play among the five offensive linemen, but he was the power sweep's poster boy.

Over the past week, I spent hours watching Packers running plays from the 1960s, jotting down questions and then seeking answers from Bratkowski; John Roach, Starr's previous understudy from 1961-63; and Ken Bowman, the center for most of Lombardi's final four seasons and the one who made the only pre-snap line call the power sweep required.

Previously, I had interviewed three of Lombardi's offensive assistants about the power sweep – Bill Austin, Red Cochran and Bob Schnelker – and several players, including Kramer, Gary Knafelc and Chuck Mercein.

Here are some of the things I learned from their tutorials.

There were a lot of Packers running plays identified as "power sweeps" in live broadcasts and highlight films, and perhaps there were even some inserted in Lombardi's instructional video after he died that weren't actually power sweeps.

That's not to take anything away from Kramer. If anything, besides clearing the record, it shows what an all-encompassing impact the power sweep had on the Packers' offense.

For example, next to Kramer's block in the Ice Bowl, his next most famous block was in another NFL Championship Game against Cleveland in 1965 when he led Paul Hornung around left end for 13 yards and what proved to be the clinching touchdown.

That TD was not Lombardi's patented play. The tipoffs included the formation and the fact only one guard pulled. Rather, it was a play put into the game plan the week of the game in anticipation of what the Browns might do to stop the Packers' running game, which, of course, was rooted in the power sweep.

"It wasn't the sweep," said Bratkowski. "It was from (a) brown formation. Different play. It wasn't called anything. It was a takeoff from all the inside runs where Taylor was running inside on 0- and 1-hole plays."

Super Bowl I was another big game where Kramer was highly visible pulling and leading plays, but not on the power sweep.

In what was the first game ever played between NFL and AFL teams, Kansas City played an odd front and over-shifted its defense, putting a defensive end over the Packers' tight end, something they hadn't seen against their NFL opponents. The Chiefs' obvious intent was to stop the Packers' most elemental play. However, Starr, in turn, countered by rarely calling the power sweep and the Packers won comfortably, 35-10.

Instead, Starr hammered away at the right side of Kansas City's defense with weak-side sweeps. As a result, Kramer pulled from the backside, not the play-side, and the fullback, Taylor, was the ball-carrier.

How does one tell if a play was a power or "Lombardi Sweep and not something else?"

Here are the things to look for.

It was run from a split-back formation where the two backs were parallel and lined up behind and just to the inside of the offensive tackles.

The play call in the huddle was "Red Right 49."

It was man blocking and it didn't vary much.

There was really only one pre-snap decision for the linemen and that was made by the center, Jim Ringo through 1963 and then Bowman. At the line, against a 4-3 defense, the center eyed the middle linebacker and the onside defensive tackle and made his one call, which also affected the offensive right tackle.

If the center determined he could cut-block the onside tackle, then the Packers' right tackle, usually Forrest Gregg, blocked the middle linebacker. If the center took the middle linebacker, the right tackle blocked down on the onside defensive tackle.

The other blocks were pretty much set in stone except for certain adjustments that could be made on the fly. In fact, Bowman told me he never once made a line call on a power sweep that changed anything the guards did.

The tight end – Knafelc in Lombardi's first two seasons, then Ron Kramer and later mostly Marv Fleming – almost always lined up nine feet outside the right tackle and blocked the linebacker. The flanker, usually Boyd Dowler until Carroll Dale was acquired in 1965, also lined up to the tight end's side and blocked the strong safety.

Three linemen always pulled on the power sweep: the two guards and the weak-side tackle, usually Bob Skoronski. If there weren't three linemen pulling, it wasn't a power sweep, although Skoronski was instructed to either cut up-field at the first sign of an opening to seal the other defensive tackle or legally run up his back along the line of scrimmage.

The fullback was a blocker. His assignment was to make a beeline to block the defensive end.

The left halfback, Hornung or Tom Moore early and mostly Elijah Pitts or Donny Anderson later, carried the ball.

Lombardi made that clear while diagraming and addressing the play in his instructional video. "The halfback is the ball-carrier on the power sweep," he stated emphatically.

Yes, I know there are two plays in the documentary "Run to Daylight," where it appeared Taylor was running the power sweep to the right behind two pulling guards. And he may have been. Lombardi put in occasional wrinkles where Taylor might have lined up as the left halfback.

In truth, it's hard to tell because so many shots in those 1960s highlight films were taken from field level and were tightly cropped. So it's usually impossible to see all 11 men and determine the formation.

On at least one of Taylor's runs in "Run to Daylight," Moore appeared to be the other back and Bratkowski said because of his unusual blend of size and speed he'd flip-flop positions. Therefore, there likely was a better chance of the play being a power sweep than if another halfback had been on the field.

"Tom Moore could play both halfback and fullback," said Bratkowski. "But very seldom did Jimmy (Taylor) run it from split back. We may have run it, but it was not a high-frequency play."

In other words, just because Taylor was running right behind two guards didn't make it a power sweep.

Bratkowski said there also was a rarely used toss play out of a blue formation that looked like the sweep and called for Taylor to run to the strong-side behind the two guards. In the blue formation, Taylor would have been on the weak side of a two-back set. What's more, the two wide receivers would have lined up to the right with the tight end to the left.

Although it was a play used more for rollout passes and in the two-minute offense, Bratkowski said it was the play-call when Taylor busted an 84-yard run for a touchdown against Detroit in 1964.

Back to Kramer and his assignment in the power sweep.

When he pulled, his first leg or lead foot had to be precisely at a 45-degree angle. He also had to perfectly time his pull so the fullback could pass in front of him in his haste to block the defensive end. Lombardi also preferred that Kramer stayed to the outside before he made his turn.

In "Run to Daylight," Lombardi had a one-word description for Kramer's talents as a lead blocker on the power sweep and it was a word he didn't use often.

"Great."

Kramer also was part of an offensive line that many around the league believed was the key to the Packers' success under Lombardi, especially early.

Included in that group was Cleveland's legendary coach Paul Brown, who won three NFL championships and four others in the All-America Football Conference, all by 1955.

"Paul Brown traded me to the Packers and he said, 'You're going to love being with the Packers. They have the greatest line. I've never seen any line get off in unison like the Green Bay line does,'" Roach said of Brown's parting words to him.

Once in Green Bay, Roach, who started his pro career five years earlier with the Chicago Cardinals, said it didn't take him long to determine, "Jerry Kramer was the best right guard in the game."