They call it "The Book," though it has no pages, no actual printed words and no known author.
It is the body of conventional wisdom, culled from nearly 150 years of baseball, that has served as silent mentor to every manager who ever decided to go for the win on the road or play for a tie at home.
The unwritten rules of baseball strategy might as well be chiseled in stone, because there is real peril in ignoring them.
Never intentionally put the tying or go-ahead run on base? Seems logical enough.
Don't make the first or third out at third base? Makes perfect sense.
Walk Barry Bonds with the bases loaded to move the winning run into scoring position, as former Arizona Diamondbacks manager Buck Showalter did a couple of years ago? What was he thinking?
Showalter got away with that bold decision, but most baseball managers would think long and hard before going so far against the accumulated baseball knowledge of the ages.
"There are obviously reasons for those rules," Orioles manager Mike Hargrove said. "They are really kind of rules of thumb. I've never seen them written down as inviolate."
Indeed. Most managers admit to bending the unwritten rules on a regular basis. Bonds often is used as the perfect example of why it sometimes is acceptable to put the go-ahead run on base. When the percentages outweigh the downside risk of bucking "The Book," a lot of managers end up chucking "The Book."
"There are people who walk the go-ahead run all the time," Hargrove said.
"You just don't make it obvious. You just make sure your pitcher throws four horrible pitches. We've done it two or three times this year."
New York Yankees manager Joe Torre has ascended to the status of Yankees legend with a managerial style that is both orthodox and occasionally spontaneous. There was a time when his managerial acumen was called into question because of his so-so level of success in three previous major-league managerial assignments, but he can afford to write his own book on baseball strategy now that he has four World Series titles.
He plays by most of the unwritten rules, but he said recently that he won't be bound by any of them.
"If you concern yourself with making moves so it's easy to answer the questions after the game, you're doing your players a disservice," Torre said. "A lot of it is feel. I don't think I ever managed totally by `The Book.'
"I never took `The Book' over what I thought was the better move ... the better chance to win."
Torre learned a long time ago there often is a price to pay for that kind of independent thinking. He walked the potential go-ahead run in back-to-back games at Wrigley Field when he was managing the New York Mets in the late 1970s.
"I did it two days in a row in Chicago," Torre said. "I walked Bill Buckner with a man at second base to get to Dave Kingman and he hit a home run each time. But to me, Buckner was a better hitter. I got crucified for it, but I never second-guessed myself."
Instinct over sense
In a lot of cases, an important managerial decision comes down to a choice between instinct and common sense. Showalter, with his controversial decision to walk Bonds with the bases loaded, went on instinct. He was willing to give up a certain run and move up two other runners even though the statistical likelihood of Bonds' hitting a game-winning extra-base hit probably was below 20 percent - less than the chance of any ensuing hitter delivering a two-run single.
The move worked, and Showalter was genius for a day, but the admonition against intentionally moving the tying or winning run into scoring position makes too much sense to ignore.
Most of the unwritten rules are like that. No self-respecting manager would play the infield up in the early innings of a tight game, because the benefits of cutting down a single run at the plate are outweighed by the possibility that a cheap hit through the drawn-up infield could lead to a much bigger inning. But there are instances - such as when Randy Johnson is throwing bullets for the other team - when that one run might be the most important run in the game.
Not many managers would pitch to the other team's top clutch hitter with first base open and the potential winning run at second base in the ninth inning, but Los Angeles Dodgers manager Tom Lasorda made an exception during the 1985 National League Championship Series.
He allowed reliever Tom Niedenfuer to pitch to Jack Clark in that situation, and he's still kicking himself. One big swing later, the Cardinals had scored three times and the Dodgers were headed home for the winter.
In that case, Lasorda was caught between an unwritten rule and a hard place.
He chose to pitch the right-handed Niedenfuer against a right-handed hitter he had struck out the last time they had met. The alternative was a bases-loaded situation in which opposing manager Whitey Herzog would get to dictate the matchup.