My interest in military history led me some years ago to make the acquaintance of a 17th century Japanese warrior named Miyamoto Musashi - arguably the greatest swordsman of all time.

His no-nonsense combat tutorial, The Book of Five Rings, was recommended by a friend. I found a copy in a bookstore's business management section, where executives searched for strategic insights.

In many ways the book parallels and sometimes surpasses The Art of War, written by China's Sun Tzu 1,000 years earlier.