ELV scrums and the 5m offside line

The ELVs introduced an offside line five metres behind the hindmost feet of the scrum. Here's a recap of the technical and tactical impact of these on the game.

1. Technical change

A good disruptive scrum can reduce the 5 metre advantage, so scrummaging in defence is important. A slight wheel towards the attacking angle needs practising.

2. Tactical changes

The tackle line

This is now closer to the gain line if not over it, which has implications for the running lines of the back row and the pack from a scrum.
The first attacking pack players now have better forward momentum at the first ruck, perhaps allowing quicker ruck ball. This can mean a faster second phase move, so the backs have to realign quicker than before.

Attack - back row moves

Close to the scrum back row moves retain their relevance in terms of tying in the opposition pack. However the extra space means your number 8 (eightman) has more options to attack the space in front of the opposition fly half (10).
Other players can feed off your 8 (or 9, the "scrum half") if he picks and goes, because the opposing flanker will be pulled out of position to cover the attack. (In defence, it is likely that the flanker will cover wide and the number 8 will fill in next to the scrum.)

Attack - backs moves

From scrums, the attacking team has more time and space to move the ball wider, thus reducing the chance that the opposition will block the move at outside centre (13).
The defence either has to drift or go up and out. On a drift there will a gap inside the fly half, with the up and out there will be space outside the 13 or winger.

Defence

How do your back line and back row defend from scrums?
Your flanker is now about 7 metres in front of your 10, not 2 metres as before. This causes a bigger dogleg in the defensive line in the area where the flanker covers inside the 10.
When breaking from the scrum, the defensive flanker now either needs to slow down a little or cover across more, leaving the gap inside to be covered by your number 8, or the lock packing down on that side.