Whilst attack off 9 is very important these days the linkage between 9 and 10 is equally as important.
The term linkage means that the attack shape off 9 and the attack shape off 10 are linked and the defence have to defend both areas of the line – the ruck and the next transition line.
The classic example is when you have 2 runners off 9 with 10 then being flat enough to receive the ball having both inside and outside options available.
The defence needs to jam on the runners off 9 and that leaves space for the 10. If they don’t jam then the option is on for the 9.
The Springboks in 2007 were terrific at this.