SANTA CLARA – The 49ers relied on a simple formula in 2011:

A heaping of takeaways

+ an excellent defense

+ a cautious offense

= wins.

The equation was sound throughout the season and took the 49ers to within a step of the Super Bowl. But in the NFC Championship Game, the formula failed.

The 49ers nailed the defensive part of it – Justin Smith and company were relentless as the game went on and frustrated New York Giants quarterback Eli Manning into a ho-hum 74 passer rating after halftime.

The offense played to form, too, committing no turnovers, taking the lead in the third quarter and then tying the score with David Akers' field goal in the fourth.

It was the takeaway portion that didn't come through.

Going into the game, the 49ers had forced a league-high 43 turnovers.

Against the Giants, they had zero, although they had chances. Two would-be interceptions in the second half were squandered when safety Dashon Goldson crashed into the cornerback. Another possible takeaway, a forced fumble that would have almost assuredly given the 49ers the lead late in the game, was wiped away by a quick whistle.

The 49ers had no takeaways only two other times during the season. The first was in a narrow win in Detroit, a game in which the 49ers' defense had a key safety. The second was in the loss in Baltimore.

The Giants game illustrates the nature of takeaways – they're fluky. They pour in like a monsoon one moment and dry up like a desert the next.

The 49ers finished the regular season with the NFL's best turnover differential at plus-28. The next-highest differential in franchise history was plus-22 in 1981. But that was followed by a minus-8 in 1982.

So while the 49ers – and every other team for that matter – will shoot for a bumper crop of takeaways in 2012, they can't be relied upon and can't be such a crucial component of the team's winning formula.

History shows that teams rarely duplicate their sterling differential from one year to the next. Also, the two 49ers players directly responsible for the most takeaways, cornerback Carlos Rogers and Goldson (six interceptions each) are free agents and might not be back.

With that in mind, the 49ers need to focus their efforts this offseason on bolstering the weakest part of their winning formula, the offense. The passing game finished 29th in the league in the regular season and was particularly conspicuous by its absence against the Giants.

Alex Smith completed one pass for three yards to a wide receiver in the game and had trouble finding open targets during the 49ers' critical, but ultimately fruitless, offensive drives in the fourth quarter and overtime.

Michael Crabtree, who had five catches for 28 yards in the playoffs, is a good wide receiver who would be an even better one with a legitimate threat opposite him. He didn't have that against New York. More than that, Crabtree and Kyle Williams are the only wideouts signed beyond this season.

There should be several highly regarded wide receivers on the free-agent market, including three – Kansas City's Dwayne Bowe, New Orleans' Marques Colston and San Diego's Vincent Jackson – who fit the 49ers' profile for big, physical wideouts.

Any one of them would be an upgrade, but it would be an expensive acquisition and one that might upset the harmony in the locker room.

The more likely route is through the draft.

That's where the 49ers went in 2010 when they needed to plug holes in the offensive line. And it's where the 49ers went last year, with second-round pick Colin Kaepernick, when they were short on quarterbacks.

It's where they're likely to search for a receiver this season. The 49ers pick 30th overall.

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