While the Chiefs face the challenge of dramatically improving in most areas, there’s also an area in which their challenge will be to remain just as good.

That would be the pass rush, where the trade of NFL sacks champion Jared Allen to the Vikings leaves a “vacancy” sign. Thanks largely to Allen’s big year, the Chiefs ranked behind only the Super Bowl teams, the Giants and Patriots, in sacks per pass play.

That’s a better gauge of a team’s pass rush than total sacks because the more passes a defense faces, the more sacks it should get. Though the Chiefs’ 37 sacks were not a dazzling total, they registered sacks on eight percent of pass plays. The Seahawks, who ranked fourth in the league, totaled 45 sacks but also faced 568 throws, 106 more than the Chiefs.

Considering the Giants’ Super Bowl victory was achieved largely by harassing quarterback Tom Brady, you might be tempted to revise the old saw from “defense wins championships” to “a pass rush” wins championships.” That would, however, be an oversimplification.

While any team would be hard pressed to win a championship without a strong pass rush, that’s only part of the puzzle, as the Chiefs showed during a 4-12 season. Six teams among the top 10 in sacks per pass made the playoffs. But the others had losing records – the Chiefs, Bears, Dolphins and Broncos.

How do you effectively pressure the quarterback, yet still lose? For the Chiefs, a 31st-ranked offense was the primary answer. But not the only one.

If you can’t shut down the run, opponents don’t have to throw so much. The 2007 Chiefs ranked 28th in total rushing yards allowed and 25th in yards allowed per rush, so opponents usually chose the path of least resistance.

If a team can’t take leads deep into the fourth quarter, which should be prime time for pass rushers, opponents can just sit on the ball. That’s what happened repeatedly to the Chiefs during their nine-game losing streak. Their pass rush didn’t get a lot of work in the fourth quarter.

Compensating for Allen’s departure, obviously, would be no small feat. Former left end Tamba Hali has moved over to Allen’s weak-side spot, and former right tackle Alfonso Boone has moved to right end. Top draft pick Glenn Dorsey fills Boone’s old spot, next to Ron Edwards.

Herm Edwards’ Tampa 2 defense – and any defense – is at its best when the front four can bring the brunt of the pass rush and allow seven defenders to blanket receivers. The 2007 Chiefs got 28.5, or 77 percent of their sacks, from the line.

The Giants’ front four totaled 44, or 85 percent, of the 52 sacks that were credited to individuals. Five linemen accounted for 42 sacks, led by three ends compiling nine or more. The Giants’ pass rush should remain strong and deep, even after Michael Strahan’s retirement.

The Chiefs, meanwhile, will go to training camp with one proven pass rusher, Hali, who led the team in sacks two years ago. Even if Boone makes a successful transition, the starting ends must be kept fresh, which is why Turk McBride, a second-round pick in 2007, must be ready to contribute more.

Blitzing is one way to add spark to a pass rush, and Derrick Johnson, who had four sacks last year, is the Chiefs’ top blitzing linebacker. Every blitz is a gamble, though. Whenever an offense picks up a blitz, a receiver should be open for a big gainer.

But the 2008 Chiefs are committed to taking their fair share of risks. With as much rebuilding and uncertainty as they still face, they’re in no position to play it safe.