SEATTLE — These two teams have more than a division in common.

SEATTLE — These two teams have more than a division in common.

The Seahawks and 49ers share a style of play that starts with a big-bodied defense, includes a hardheaded insistence upon running the football, and continues through a fixation on turnovers that could be diagnosed as clinically obsessive. That's the blueprint that has taken San Francisco to its first division title since 2002, and it's the recipe that explains how Seattle has rebounded from a 2-6 start.

"The formula has been very similar," coach Pete Carroll said.

That's what makes today's game at CenturyLink Field so very intriguing. Something's got to give.

The Seahawks have won five of their past six games in large part because they forced 18 turnovers in those six games; the 49ers have committed a league-low 10 turnovers all season.

Marshawn Lynch has scored a touchdown in each of his past 10 games, a Seahawks record. The 49ers haven't allowed a rushing touchdown this season, something that is truly remarkable even if the 49ers aren't pondering the historic possibility of being the first NFL team since the Great Depression to go a whole season without allowing one.

"You really don't have time to sit around and pat anybody on the back," 49ers defensive lineman Justin Smith said. "We're just back on to it, and this week will be a heck of a challenge (with) the way Marshawn is running and the way they're blocking up front."

In a league increasingly littered with gaudy passing totals, the Seahawks and 49ers are taking a more old-fashioned approach by buckling their chin straps and running headlong into the defense, then lining up and doing it again. Pretty? No. Effective? So far.

"We want to be a winning offense, really," 49ers coach Jim Harbaugh said. "That's what we want to be. I think so many people want style points and that's a bit irrelevant."

His Seahawks counterpart agrees.

"We're not trying to win any popularity contests," Carroll said. "We're just trying to win games and play well."

It wasn't so long ago these franchises shared a lineage in the West Coast passing offense. Now, both teams rank in the bottom third of the league in passing yardage, their quarterbacks operating under similar instructions. It's not just the plays Alex Smith and Tarvaris Jackson make that are important, but the mistakes they don't.

"We don't want the quarterback to be the guy that has to carry the whole load," Carroll said. "There's going to come times when they do."

The similarities are so striking that it's tough to discern just what the difference in Saturday's game will be. Could be that the Seahawks offensive line will be manhandled by a 49ers defense that kept the Steelers from scoring a touchdown five days ago. Or perhaps San Francisco will be frustrated by an inability to push Seattle's defense around and start taking the kind of risks the 49ers have been so good at avoiding.

Or maybe the strengths will cancel each other out, and one of the quarterbacks who has been praised for avoiding mistakes will step up to make a difference.

The NFC West title is already decided, but that doesn't dilute the game's significance. Playoff possibilities remain at stake on both sides, plus these two teams expect to be slugging it out for the next few years. Round 1 went to the 49ers in September. The Seahawks believe they're ready to answer the bell in Round 2.

"We've captured something that we're real proud of," Carroll said, "and now we have something to finish with. We know what we're going for and we're getting tested right in the heart of the division."