The old adage about passing is that "three things can happen when you pass the ball, and two of them are bad." While it is true that many bad things can happen when you pass--sacks, interceptions, incompletions, injuries, and penalties to name a few--many good things can happen as well.
Many teams passed their way to championships before Walsh using many of the same plays Walsh later incorporated into his offense, but Walsh was really the first to minimize and manage these risks of passing the ball. That's what made his offense so formidable.
Walsh did not throw the ball solely in an effort to generate big plays--typically it was quite the contrary. The Ball Control passing game Walsh employed aimed to gain solid yardage on first and second downs, and convert on third downs. Much of the time, this was accomplished through 3- and 5-step drops by the QB, WR and TE routes breaking at around 12 yards, and backs running routes out of the backfield.
By attempting to gain less yards per completion Walsh was also able to trade for a higher completion percentage and more consistent, steady yardage through the air.
Efficiency in Statistics
For a statistical breakdown of how this occurred, let's contrast Joe Namath's 4000 yard season (one of the best of a previous era) with Joe Montana's 1989 Super Bowl winning season stats. (Note: while Walsh did not coach the 49ers in 1989, his influence on the passing offense and Montana were undoubtedly still there.)
| Player | Year | Pass Yards | Attempts | Completions (%) | YPA | Y/C | QB Rat | TD | INT | ANY/A |
| Joe Namath | 1967 | 4007 | 491 | 258 (52.5%) | 8.2 | 15.5 | 73.8 | 26 | 28 | 5.88* |
| Joe Montana | 1985 | 3521 | 386 | 271 (70.2%) | 9.1 | 13.0 | 112.4 | 26 | 8 | 8.31 |
*The NFL did not record sack stats during the 1967 season, but Namath was sacked 5% of the time in his career from 1969-1977. If he had an average year, Namath would have been sacked 24.5 times for 236 yards
A quick comparison notes that both QBs threw for a lot of yards. While Namath threw for more yards per completion, Montana threw for more yards per attempt. A trade of smaller plays for efficiency is typical of a Walsh offense. This sort of more consistent offense is more likely to move the chains.
One stat that jumps out at me is TD:INT ratio. While both teams counted on their QBs for scoring (each having 26 TDs), Montana threw 8 INTs compared to Namath's 28. Any coach would love to eliminate five turnovers a year, let alone 20.
Pro Football Reference uses a stat called Adjusted Net Yards per Attempt (ANY/A) to incorporate YPA with sacks and TD/INTs to measure a quarterback's efficiency. Comparing the ANY/A between Montana and Namath's seasons highlights the West Coast Offense's efficient approach. For comparison's sake, hall of famer Terry Bradshaw's career high ANY/A in one season is 6.6. Bob Griese's is 6.3. Walsh's quarterbacks weren't groundbreaking because of what they did (throw a lot) but because of what they didn't do (throw INTs).
Systematization
"Here is natural instinct, and here you have control. You are to combine the two in harmony. If you have one to the extreme you will be very unscientific, if you have the other to the extreme you become a mechanical man. You need a successful combination of both." -Bruce Lee
Walsh's system of utilizing the forward pass was highly disciplined and structured. His quarterbacks had to have an automatic response to defenses, knowing where, when, and why to throw. They drilled the plays and reads they would use so much that they would become second nature for a quarterback.
Walsh was able to demand perfection from his teams because when they paid attention to detail they saw results. Our own Mike Holmgren once wrote about Walsh:
"As the 49ers' quarterback coach I watched Joe Montana throw a pass slightly behind Jerry Rice, who nevertheless would catch such a pass 99 times out of 100 (note: the legend is that this pass was was actually complete and went for a touchdown).
Most coaches might be satisfied with this success ratio. Not Bill. He immediately came to me and explained in great detail why a pass involving that route had to be thrown twelve inches in front of the receiver, not six inches behind him.
Bill had a singular focus on perfection. Every Day. Every practice. Every play. Every meeting. Every situation."
Walsh demanded such accuracy from his quarterbacks. Not only would they be taught which receiver to throw to and why, but where the ball needed to be in relation to the receiver. Too far in front and the he might be vulnerable for the big hit, too far behind and he might have to slow down and lose potential YAC. The ability to put the ball on one side of a receiver can also allow quarterbacks to "throw open" their targets, turning potential sacks or incompletions into yards gained.
Teams attempting to duplicate the success of the West Coast offense by merely duplicating their plays and schemes would be taking a fragmented approach to the system. Walsh's systematized approach meant that everything from the reads, routes, and QB drops to the playcalling to the equipment managers to the athletic trainers were in concert with one another and that his team was put in the best possible situation to succeed.
By taking a detailed, systemic approach to passing the ball, Walsh limited negative plays through the air, increased efficiency, and experienced success.