A quarter of a century ago, in a bid to induce end-of-season excitement in English football, the play-offs were introduced in all professional leagues below the top tier.
They may have been an artificial construct borrowed from American sport, but they became a roaring success. Occasionally, however, the organic model can produce something still more dramatic.
For the first time since 1994, five teams are threatened with relegation on the final day of the Premier League season. Two will make the descent to the Championship.
This is where the differences with the other May extravaganza are most marked. In the play-offs, teams have everything to gain. Today, they have everything to lose: their top-flight status, the majority of their income, their finest players and their place in the spotlight.
No wonder, then, that Alex McLeish describes it as the biggest game of a managerial career that has included more than 700 games and nine trophies. His Birmingham City side are one of the endangered quintet, along with Blackburn Rovers, Blackpool, Wigan Athletic and Wolverhampton Wanderers. Separated by one point now, they will be divided by a division next season.
This is the crossroads where underachievers and overachievers meet, where dreamers and realists part company, where one decision or deflection, one instance of inspiration or idiocy could be the defining moment of the season.
As Blackpool's top scorer DJ Campbell said: "It's do or die."
It is an afternoon where death could be determined more than 300km away. The fixture list is unfriendly to almost all, the permutations almost endless.
Wolves and Blackburn, facing each other at Molineux, could draw and go down together, but either might survive with a defeat.
The three sides immediately beneath them are all away from home, but each seemingly intimidating fixture contains a twist: Wigan are at injury-hit Stoke; Blackpool travel to Manchester United, while their hosts are preparing for the Champions League final; and Birmingham visit Tottenham Hotspur, who are aware that victory would give them a place in the Europa League.
This is a test of tactics and temperament. With characteristic caution, McLeish has warned of the dangers of going to White Hart Lane with too bold an approach. Blackpool, however, long since concluded they cannot shut up shop. They approach their mission impossible with endearing daring.
"We have to do something no one has managed this season," manager Ian Holloway said. "Beat the champions on their own ground."
Holloway said it would be "the end of the world" if Blackpool do go down. Yet, as he admitted, in another respect, it would not be. They have spent sensibly.
So have Wolves and Wigan. Birmingham and Blackburn may have the most to fear financially should they slip through the trap door.
And there are reasons to be fearful. The precedents set by clubs who slipped into League One or whose unsustainable wage bills sent them spiralling into administration represent the warning signs on the road ahead.
Talk of budgets at Blackburn, manager Steve Kean has said, are only about a plan to push on next season. His insistence the relegation was never mentioned in a meeting with owners Venky's suggests a club who are either being disingenuous or in denial.
More realistically, with 40 points and a respectable goal difference, Blackburn are aware that salvation is within their grasp. "We don't want to consider insurance policies from elsewhere," Kean said. "It's about taking your destiny in your own hands. We have got a mental mantra that is 'bring it on'."
Those words were echoed at Wigan. Having spent the majority of the season in the drop zone, they are accustomed to being written off. Yet the first of two games their manager, Roberto Martinez, has branded "cup finals" was won thrillingly, with Charles N'Zogbia's 94th-minute goal earning victory against West Ham United last week.
"We've had no fear and nothing to lose in the last two games. It's been an opportunity more than fear," Martinez said.
Positivity cannot camouflage consequences. Most of the managers involved have received assurances about their future, but they will be tested by demotion. So, too, will the loyalty of fans, with lower gates a frequent result of relegation.
Meanwhile, predatory rivals take on the role of asset strippers, looking to pick off the prized players who, in many cases, do not want to experience life at a lower level.
This is a day, then, that shapes careers. In some cases, it irrevocably alters the history of clubs. The drama is feel-good story for some, disaster movie for others.
Pressure is rarely greater. But as a typically blunt Wolves manager Mick McCarthy asked rhetorically: "Am I enjoying it? I'm enjoying it all. What is the alternative - go and play golf?"