So many sacks, just one defense.

The 49ers have struck a rich vein of form this year, improving in nearly every area of the game but there is a flaw in the golden seam that they have been mining, they do not seem to be able to pick up heavy blitzes. It's been a problem all season.

After the Saints game I was leafing through Rex Ryan's superb coaching manual on the 46 defense (a great read for real football fans, it'll show you why Revis Island is actually a peninsula) and I found that one of his schemes was leaping off the page at me. I knew this defense, I'd seen it,in fact the niners have been seeing it all year and the niners have more trouble blocking this scheme than anything else that's been thrown at them.

This scheme first made its mark in preseason when the Saints pummled the 49er quarterbacks with a series of big blitzes and the niners seemed to have no answer for it. It was then seen again as the Cowboys shut the niner offense down completely in the second half and I'm sure most 49er fans are tying to forget the nine sacks that were served up with their Thanksgiving turkey. The scheme was then used in Candlestick on Saturday when the Saints defense twice forced the 49ers out of field goal range with third down sacks.

The defense is actually the standard coverage of the 46 defense and the key adjustments are staggeringlysimple. The defense aligns with one safety playing the deep middle, corners in man coverage on the outside receivers and the other safety playing close to the line, usually lining up over the tight end. From there the defense will have five designated pass rushers along with three defenders lined up in man coverage against the slot receivers, tight ends and backs. So far this is a normal Cover-1 / Man-Free defense but it's the next step that results in sleepless nights for offensive line coaches. If the linebackers see the defender they had coverage responsibility for stays in to help in pass protection then the linebacker rushes the quarterback and attempts to 'hug' the back or tight end, preventing them from helping in pass protection, releasing for a screen pass or releasing on a delay.

This is single coverage 46-style and it provides two major problems for an offense, if the defense executes properly then it is impossible to double team a defensive lineman and even worse, the more players the offense adds to its pass protection the worse their predicament becomes as more blockers mean more rushers. The chances of an offensive line managing to communicate and hit all their assignments are significantly lower as you introduce more blockers into the protection. Things will get harder if the defense adds in a stunt or a twist, the defense has as many rushers as blockers so any mistakes in passing off a stunting defender will always release a free rusher. Unable to keep the quarterback upright the offense adds more pass protectors, unknowingly making the worst possible call.

It's no suprise that we've seen this from Dallas, New Orleans and Baltimore, these coaches learned from the best. This wrinkle to the well aged Man-Free defense was devised by Buddy Ryan with the Chicago Bears in the 1980s. Gregg Williams helped to coach this defense under Buddy Ryan himself in Houston in the 90s, Rob Ryan got the scheme from his dad and Chuck Pagano learned from Rob Ryan in Oakland and Rex Ryan when he was in Baltimore.

When the niners faced Buddy's acolytes they gave up nineteen sacks in three games, which is just horrible and the Ravens are still lurking as a potential opponent if the niners win on sunday. I can only hope that they can find an answer for it, I'd suggest having backs chip against the defensive ends rather than commit to a block, for a start.