I read this in translation some years ago, and it stays with me still...I remember the image of Musashi, the tousle-haired itinerant sword saint who's beaten everyone in Japan, so no longer even bothers using a sword to duel.

Challenged to fight a famous fencing master in a dawn duel on a river island, Mushashi rows out alone and more than a little late to find his opponent and second awaiting him in their samurai finery. Our dishevelled hero has come unarmed. He leaps from the boat, breaks an oar in two, charges and kills his opponent with one blow of the oar handle.

He wrote the book in his latter days in the form of letters to his student sent from his hermit cave where he had retreated to await his coming end. Not just fencing, he (indirectly) expounds the incomparable dharma of the void.