For some time, I have been making a point of abrupt concentration. I may be idling on the sofa, and all of a sudden, I would start concentrating on something, whether it is work or play.
When I give a lecture, I would shortcut all the protocols and niceties, going straight to the point, often on the verge of conducting an attack of pleasant surprise on the audience.
I was discussing this particular piece of my philosophy of life with Prof. Tatsuru Uchida, a well-known scholar in French philosophy. Tatsuru remarked that what I had just said was actually the core spirit of martial arts. Tatsuru is a practitioner of Aikido, you know.
In the tradition of Japanese martial arts, the basic assumption is that you never know when the enemy would attack you. It is quite possible that when you are relaxing and idling away, the opponent suddenly attacks you from behind. It is therefore absolutely necessary to be able to "ignite" your system in a moment, reaching the highest level performance within a second. There is no time for "warming up". The enemy does not wait until you are up and ready. Tatsuru's comments made sense to me.
So, without knowing it, I have been practicing the core spirit of Japanese martial arts.
I am quite a peaceful person, though.