Any defence coached by Jacques Nienaber is going to have a few stock characteristics.

You’re going to see numbers in the primary line, you’re going to see line speed and you’re going to see aggression. Making defence “personal” was a key part of Jacques Nienaber’s philosophy at Munster and it’s no surprise to see the same qualities reestablishing themselves in the Springbok’s defence in year two of their term.

The Boks might not have set the world alight in attack this past weekend but their defensive work was really excellent and classic Nienaber.

So what are we seeing here?

This is a high blitz with overlapping cover.

The key principles of this system are massive pressure on or outside the #10 (Du Toit) with Mapimpi and Le Roux spiking into the All Black flank. Kolbe covers the blindside backfield in front of the ball with Pollard and De Klerk drifting into openside backfield.

Mapimpi and Le Roux blitz hard on the edge onto Barrett and Smith to choke up their running lines and pressure their possession with Marx and Du Toit swarming across to attack the breakdown. It’s a mistake to assume that big blitzing teams don’t attack breakdowns – they do, and South Africa are no exception – but you have to attack the breakdown when the numbers suit you, not the opposition.

Typically, that means attacking any breakdowns that happen here;

But you only attack those breakdowns when you have the numbers to swarm the breakdown – as the Springboks often do with their high blitz. Look at the defensive numbers hitting this defensive breakdown after the tackle;

That is a lot of Springbok forwards surging on an isolated wide ruck. Du Toit is unlucky to give away a penalty here in that he’d probably have won a penalty had Malcolm Marx managed to keep his footing in his attempt to “brace” the jackal.

The slowdown achieved here plays into one of the Springboks’ chief defensive aims – they want you to play wider.

Look at the formation around this ruck once the ball comes loose.

Kwagga Smith aside, that’s a massive forward defensive line. There are no easy one-out plays here and the All Black’s structure shows their need for width and depth. This is where the importance of South Africa’s midfield defensive hitters comes into play.

If the All Blacks were going to play wider to avoid battering into the heavy Springbok fringe defence, then the tracking and hitting of Damien De Allende and Lukhanyo Am would be vitally important. If we go back and look at that All Black’s attacking structure, it seems designed to put the ball into that wide pod of Retallick, Todd and Taylor with Williams on the screen.

If that happens, Am and De Allende have to drive hard into the All Black second layer to invade their attacking space.

The more hands the All Blacks put on the ball, the slower their attack will become from a time perspective. If it takes 3/4 seconds to spread this ball to Williams, that gives Am and De Allende 3/4 seconds to take the space and allow the overlapping forward cover (white box) to move up and out to secure the space behind them and populate the next ruck.

You can see Am signalling to De Klerk to narrow his line and join this blitz;

This follows the same principle of the previous ruck where the edge defence has to spike into the attacking layers in unison to pressure the attacking space with Pollard covering the break and the kick option in the backfield.

The angle of De Klerk’s blitz has to be closely tied to Am’s blitz line or else South Africa run the risk of giving up a central break.

In practice, this means that South Africa are OK with giving up the outside for a slow, wide pass. In the above example, the danger player from a Springbok perspective is Ioane.

If the ball gets to the middle pod of three players with Williams (Black #12) on the screen, then a floating pass to Ioane is a target but the Boks don’t drift for that option immediately. They want to pressure the attacking space with a high edge blitz.

If Retallik, Todd or Williams takes this ball, the Bok edge blitz will take them out and effect the tackle.

If Mo’unga hits Williams and the pass floats out to Ioane, the Boks can use the “ball in air” time to surge on Ioane and use the touchline to defend the break.

Pollard can track the break while Kolbe rotates into the backfield with Le Roux recovering to take the openside backfield.

That can only happen in an organised way with De Klerk tightening his line on Am.

If De Klerk keeps on the outside of Am without tightening the blitz, you give up a chance at an inside break and create an isolation on the edge defender.

So you go all at once and tight, or not at all, with the second last edge defender leading the line speed and taking the space, with the last edge defender surging up to cut off the offload.

Here are a few examples;

When you know the opposition is going to want to play wider to gain ground (rather than try to attack your fringes) you can afford to give your midfielders a licence to read and blitz.

This system isn’t without its weaknesses, of course. A good kicking game at the edge can catch out this system – as we found at Munster – and a team with more heavy ball carriers than the All Blacks can test the fringes in a way that could challenge the fold decisions of the Boks in a centre-field position.

If the Boks give up that fringe dominance against a side like England or Ireland, then the entire blitzing system falls away. We saw in Munster how losing physical dominance around the fringes in centre-field led to the system falling down and while the Boks are certainly stronger around that fringe than Munster were in 2016/2017, the same issues apply with regards to this system.

That shouldn’t take away from the excellence of this defensive performance, however, and Erasmus will take a world of confidence from their showing here.