The rook on a7 can be quite bewildering for someone who doesn't know this opening, but as Ris mentions, this is the right way to defend the pawn on b7. In the above position we see in practice the meaning behind Ris' words. Since different openings teach the difference of importance of the different pieces, their placement, the different tactics which we are exposed to in different openings. This will limit the chess understanding they will gain. Some people only want to learn one opening. Why is this important? Because with the same amount of training hours, let's say a minimum of 10 hours a week, the younger brain will be able to store more information from short term memory into long term memory. A young player's brain – and today if he is not already a GM at 12, he should consider another career – has not the same level of hormones and neurotransmitters that my old nearly 54 years old brain has. Then of course there is the age of the brain. Passion for the game makes a big difference in the amount of hours one spends studying chess, instead of watching the latest flick on Netflix. So where is the trick one could ask? Well, the problem is definitely not a magical "talent" but memory and the brain.
Ris begins the DVD with the well repeated chess mantra: "everything in chess is pattern recognition". Particularly when you have been confronted with a surprise opening system played by your opponent, it helps when you can just Pattern recognition is an important tool in modern chess, as it helps you to understand better the characteristics of a position.
Mastering Pattern Recognition in the Opening