On Saturday, the Redskins will play out the final hours of what has been a week-long chess game between their coaches and the staff of the Minnesota Vikings.

It's blindman's chess based on hours of film and computer study, on-the-field practice and classroom instruction. And checkmate is the final score.

This remarkable long-distance chess match is orchestrated by one of those wonderful football mysteries: the game plan.

Players are fined for losing game plans. Coaches refer to them in general terms; ask them to discuss specifics and it's as if they were being requested to part with a state secret.

The in-season lives of players and coaches revolve around the game plan, a hefty, 30-to-40 sheet mimeographed packet handed out weekly at Redskin Park.

Those sheets are the result of a combined 60-70 hours of work by the offensive and defensive staffs. Within those pages are the tactics the players will use Saturday against the Viking riddle.

"No well directed business would go about operating without a blueprint," quarterback Joe Theismann said. "That's the same theory with the game plan. We just don't show up on game day and free lance. It just doesn't work that way."

The Redskins began preparing for the Vikings last week, even before either team had gotten past the first-round of the playoffs. The coaching staffs broke down Vikings films, charting out each play over a two- or three-game period.

Eventually, at least three game films were analyzed. A computer study of the Minnesota defense was run off. The coaches studied tendencies: what kind of offense or defense will the Vikings likely play on certain downs, at certain points on the field, at certain stages of the game, at certain scores, with certain players in the game? And what can the Redskins do to be effective in each of those circumstances?

The preparation was so detailed that Nate Fine, the Redskins' veteran film man, even put together film clips (to be seen later by the players) of Viking games, with one reel showing all plays selected opponents have run against Minnesota inside the 20-yard line, another showing short yardage plays, another third-down passes.

On Sunday night, coaches began turning all the information into a formal game plan. The work continued all day Monday, so by Tuesday morning, when the players reported for their first practice, the initial part of the plan was instituted.

Defensive players were introduced to tactics they will use against Minnesota on normal down and distance. Offensive players received plans for all first-down run and pass situations and a good portion of third-down passing situations. Everything was carefully reviewed, both through instruction and film study, then it was practiced that afternoon on the field and filmed for review that night by the coaches.

"What we don't like we change," said Dan Henning, the Redskins' assistant head coach. "What we like, we keep in. But everything is tested thoroughly before it is used on Sunday. For example, we may want to run a certain play against two different defenses. Before the week is out, we'll make sure we try it that way in practice."

Over the next two days, the rest of the plan was handed out, then practiced, filmed and reviewed some more. And the players were given a chance to respond.

"If we aren't comfortable with something, we'll say so," safety Mark Murphy said. "The coaches are very good at listening to us and making adjustments. They realize we are the ones who have to execute it."

The players on both offense and defense who are responsible for relaying coaches' signals to teammates on game days put in extra hours going over the plan. Theismann, for example, came in an hour early three days a week to start studying. By the end of each day, he had gone over the plan three times, twice in meetings that will last up to a total of three hours.

"A lot of the information is familiar but Joe Gibbs must be the father of invention," Theismann said. "He uses the game plan every week to challenge us with something new. It keeps things exciting."

On Saturday, Gibbs, who calls offensive plays, and Richie Petitbon, who signals defenses, will refer frequently on the sidelines to large cards. Those cards contain the final game plan. Gibbs and his assistants may have rewritten the offensive plans 10 times during the week, changing play priorities or deciding that instead of having 14 plays that will work in a certain situation, there may only be nine.

There may be only 12 running plays and 25 passes on Gibbs' card, but the Redskins could wind up using one run seven times in the game, and never once from the same formation.

If the Redskins are at midfield, first and 10, with the game tied, Gibbs needs only to refer to the card to see what defense the Vikings likely will be in, and what plays the coaches have decided will be effective against that alignment.

"We always put in more than we think we will use," Petitbon said, "because you never are sure what you are going to need. You think you've anticipated but sometimes the game unfolds differently and you wind up relying more on one defense than you thought. We've got one blitz we've practiced for 12 weeks and haven't used yet."

Still, the Redskins do very little free lancing. "If we've prepared adequately during the week, there is no need to vary from the plan," said Henning. "It comes down to this. We try to predict, when things are on the line, when it's a gut check situation, what the other team will do. The closer we are to being right those times, the more successful we'll be."

And when those predictions come true, when Henning can see a week's work pay off with a successful play, he says he is exhilarated.

"The only thing better is playing," he said. "That's what makes the work worthwhile, that's what keeps people in this business."