This quotation from the introduction to The Book Of Five Rings discusses what Zen is.  The Zen of bushcraft, then, is doing something so many times that doing it becomes second nature.

“In Zen first comes the technique, practiced so many times that it is forgotten.  Then you begin to use it.  It is when you do not think about it anymore that you do it so well.  Zen is no more than that.  But it is reaching that state that the training is all about.  The professional dancer who makes it look easy has trained constantly and endured great pain.  The tennis pro who flies around the court, making impossible shots, does so not because of any superhuman qualities but because he has practiced and practiced, as the dancer has, until the movements are internalized.  There is no longer any conscious direction in the movement.  When you marvel at the way someone whips up a dinner for ten on short notice, or the way someone makes an impromptu speech, you are marveling at the same thing – the approach, the confidence, the naturalness of the behavior.  There was no time to prepare, no time to think, no time to hesitate.  There you are.  Zen.

– The Book Of Five Rings, Introduction, p. xxv