It's a given that the Packers' venerable and storied "relationship" with the Chicago Bears, now well into its ninth decade, is a rivalry apart.
Just for sheer frequency alone. The immemorial antagonists have clashed no fewer than 166 times over their mutual, 83-year history - and thus remain the only two teams in National Football League annals to have squared off on more than 150 occasions.
And that is not to reference the competitive intensity that has typified this hallowed neighborhood feud, launched in 1921 when Warren Harding was in the White House. Remarkably, the average point differential over those 80-plus years and 166 contests is less than one point per game!
Additionally, the ancient enemies were the principals in the very first divisional playoff game in NFL history, a showdown staged in Chicago's Wrigley Field in 1941 after they closed out the regular season in a tie for Western Division honors with matching 10-1-0 records.
In view of such distinctions, it should come as no surprise that the classic series also has been punctuated - not once but twice - by one of the rarest plays in pro football history.
Going by the NFL rule book, it is officially known as the "fair catch kick."
Simply put, the rule states: "After a fair catch, the receiving team has the option to put the ball in play by a snap or a fair catch kick (a field goal attempt) - with fair catch lines established 10 yards apart."
The latter, incidentally, means that the defending team must be 10 yards removed from the scrimmage line of the kicking team and cannot "rush" the kick, which thus, as the name implies, is a "free" kick.
The Packers, then under the direction of Vince Lombardi, "introduced" the maneuver - a genuine rarity in league history - to a capacity house of 42,327 fans in their 1964 regular-season opener against the Bears (Sept. 13) in what was then known as City Stadium (it was to be renamed Lambeau Field just a year later, following the death of team founder E.L. "Curly" Lambeau).
With only seconds remaining in the first half, Elijah Pitts, back to receive Chicago's punt from Bobby Joe Green, signaled for a fair catch as he fielded the football at the Packers' 48-yard line.
Next, to the surprise of the full house - and virtually all members of the attending media -Lombardi informed Referee Norm Schachter that the Packers would be attempting a fair catch kick on what would be the final play of the first half, and the Green and Gold promptly lined up across the field, 11 strong, with quarterback Bart Starr remaining in the game as a holder at the line of scrimmage.
Paul Hornung, once again the Packers' placekicker after sitting out a one-year suspension in 1963, advanced to kick the ball out of Starr's hold -- and it sailed through the uprights, padding the Packers' lead to 17-3 as the first half ended.
Hornung's 52-yard success tied the team's existing field goal distance record, which had been set by Ted Fritsch on Oct. 19, 1950, against the then New York Yanks at Manhattan's Polo Grounds.
Although the free kick field goal was not a major factor in the game's outcome (the Packers eventually prevailed, 23-12), the Bears, it turned out, did not forget.
Four years later, they invoked the same rule to turn the tables on the Green and Gold and pull out a victory in Lambeau Field.
It was Nov. 3, 1968, in the year Phil Bengtson succeeded Lombardi as Green Bay's head coach, with Lombardi staying on as general manager.
In retrospect, it seems somewhat surprising that the Midway Monsters needed a field goal to settle the issue that afternoon because Gale Sayers, the Bears' gifted running back, was having a career day, amassing 205 yards rushing to set a then-Lambeau Field record.
But it was a tightfisted, 10-10 standoff with just 38 seconds remaining in the game, when Cecil Turner, back to receive the Packers' punt from leftfooted Donny Anderson, signaled for a fair catch and fielded the football at the Green Bay 43-yard line.
The Bears immediately made known their intentions to Referee Pat Haggerty and lined up in kick formation, whereupon their specialist, Mac Percival, sent the free kick over the crossbar to seal a 13-10 Chicago victory.
That was 35 years ago and the Packers have not "called" - or seen - the like of it since.
Lombardi, erroneously, it turned out, had predicted that the one he had called for in '64 would remain one of a kind.
During his press conference following that game, he had volunteered, "The chances of your seeing it in your lifetime or my seeing in it mine again are nil."
Although mistaken, Lombardi was not far off.
Art McNally, who launched his NFL officiating career in 1959, headed the league's officiating department from 1968 to 1990 and currently remains the NFL's assistant supervisor of officials - a 45-year span, readily testifies to the infrequency of a free kick.
Acknowledging the league has no record of how many times the rule has been invoked, McNally declared, "I would be willing to bet that it would be no more than six...all-time."
He added, "That one (by the Bears in Lambeau Field in '68) might have been the last successful one."
Why is it such a rarity?
McNally offers a logical explanation.
The opportunity, he points out, "is always there - the fair catch kick can be called for at any time in the game. But, generally, if you fair catch a punt where you could attempt one (with any appreciable time on the clock) you're probably going try to score a touchdown."
Following the game punctuated by Hornung's free kick in '64, Lombardi was jovially candid when asked if he and his team had "worked on" the play in practice.
"We've never worked on it in our lives," he asserted.
He added, in explanation, "We almost faked ourselves out....You saw the confusion (on the Packers' bench when the kick was called)."