Building walls

I was interested in what Rob wrote on his blog regarding building defensive walls; whilst there is a time and place for defence it's a dangerous mind-set to get into because it can lead you to become passive. Musashi discusses this in the Book of Five Rings when he talks about positions of the sword. He says, "In the course of struggle for victory by military science, the thing is to concentrate on seizing the initiative and getting the jump on others in everything. The sense of a guard or defensive posture is that of awaiting the initiative. This should be worked out thoroughly".
In other words Musashi is advocating action not inaction; attack as defence. He then finishes off the section with "there is a totally different feeling in being attacked by others first than in attacking others yourself. The sense of being able to wield a sword well enough to catch and parry an opponent's blows is tantamount to taking your spear and halberd and sticking them in the ground as fence posts. When you are going to strike an adversary, in contrast, you can even pull up a fence post and use it as you would a spear or halberd...."
What is he saying here? Well my intepretation is that there is a total difference in attitude between passive defence and aggressive attack. If you are passive you are awaiting the opponents first move. You will need extremely fast reflexes to be able to deal with every attack and you will never have a chance to take the initiative. It is possible to fence like this but only for a while as eventually the hits will ge through. If, on the other hand, you take the initiative and attack your opponent you are removing his options for him and in effect greatly improving your defensiev options as your opponent will not be able to attack.
Musashi is also making the point that by deciding not to use your weapon (and skills) you may as well stick them in the ground as inert objects for all the good they do. Whilst he advocates the ability to parry well, (no swordsman can avoid all attacks) he deplores the defensive mind-set.
In contrast he makes the point that you should be able to use any situation to your advantage whilst attacking, even using fence posts as weapons. (This resonates greatly with his duel with Ganryu, whom he killed using an oar carved into a training sword - why did he use such a weapon? Well, there's a story for another day..)
Imagine what his attitude must havebeen like in combat and the energy he would have projected. Use everything at your disposal to attack and do not stop until victorious. He would have blown through most walls in an instant....