Curious Insight

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Curious Insight

The Book Of Five Rings

23rd March 2020

I'm a big believer in an idea that Nassim Taleb popularized in his Incerto series called the Lindy effect. Put simply, it's a theory that the future life expectancy of some non-perishable thing is roughly proportional to it's current age. The world has had smartphones for around 10 years so we can reasonably estimate them to be around for another 10 years or so before something replaces them. Conversely (and this really illustrates the point), the technology we call a "chair" has been around for thousands of years, so one should expect that chairs will be relevant for a long time to come. It's easy to think of scenarios where this rule of thumb fails of course, but that's not the point. It's not a statistical prediction but rather an observation about the nature of things which exist in the world but do not age (an "indicator of robustness" as Taleb put it).

The Lindy effect applies to things like technologies, but also ideas, and by extension the modalities that we use to communicate ideas (i.e. books). I've been spending a lot more time lately thinking about the age of the books I'm reading. It's easy to focus on newer books because there are so many coming out, they are well-marketed, have catchy titles, get discussed a lot on podcasts etc. But if the Lindy effect holds, it means that most of the best books in history were written a long time ago. After incorporating this knowledge into my book selection strategy, I began seeking out old but enduring books that are still in print. Such is how I came to read Miyamoto Musashi's masterpiece, "The Book of Five Rings".

A typical biographical description of Musashi would begin by noting that he was a Japanese swordsman who lived in the 1600s. But he wasn't just any swordsman - he is arguably the greatest swordsman who ever lived. Musashi famously went undefeated in over 60 duels throughout his life (many of them to the death), a streak that no one else ever come close to matching. His legend has been passed down through generations and remains deeply embedded in Japanese culture to this day.

In the later years of his life, Musashi wrote "The Book Of Five Rings" to codify the two-sword martial arts style he had spent his life mastering. Although the book is principally about the details of his study of martial arts, its true value is much broader and much deeper. Look beyond the surface and there's a life philosophy (which Musashi calls "The Way") that one can gain insights from that apply to all aspects of our existence.

In the book, the five rings correspond to the five "books" or sections of the text which are meant to refer to the idea that there are different elements in battle, just as there are different physical elements in life. Musashi named them Earth, Water, Fire, Wind, and Emptiness. Below are some of my notes from each section. One could describe the language Musashi uses as cryptic and hard to interpret, but to me that's sort of the point. As I read through the book, I couldn't help but feel as though every statement has a deeper meaning that would only be revealed to me upon careful, deliberate reflection. This process is still ongoing.

While I tried to capture the essence of the text in very short, concise passages, there is inevitably a great deal that was missed. Consider these notes a starting point to uncovering the wisdom embedded in Musashi's work.


The “Way” of something is a learned discipline or philosophy (i.e. the Way of Buddhism, the Way of the Carpenter). The Way of Martial Arts, which Musashi refers to as “Two Heavens, One Style”, is to learn skills that are useful in all things. The Way of the Martial Arts is a mastery of one’s craft similar to carpentry, of which the sword is the essential martial art. There is a rhythm to everything. There is rhythm in the formless. Victory is in knowing the rhythm of your opponent, in using a rhythm that is hard to grasp, and in developing a rhythm of emptiness rather than wisdom.


Think deeply about the principles written in the book as though you discovered them yourself. Make them part of yourself. The mind should be centered, swaying peacefully. Be watchful of the mind and do not let it become clouded. Sharpen your wisdom. Learn the good and bad of all things. With every grip, stance, strike, do not think of the action itself. Think only about cutting down your opponent. With practice you will gradually grasp the principle of the Way.


There are three initiatives to understand in order to defeat an opponent – Initiative of Attack, Initiative of Waiting, and the Body-Body Initiative. Knowing the conditions in which you find yourself means clearly observing your opponent and grasping the way to victory with certainty. Become your opponent. Move the shadow. Control the light. Impose fear. Cause confusion. Do not use the same tactic repeatedly. The true Way of swordsmanship is to fight with your opponent and win.


The True Way does not prefer a long or short sword, a forceful or weak stroke, specialize in a stance, or fix the eyes on a particular gaze. It is not fast or slow, prefer interior or exterior positions, or dictate how to move your feet. There is no “best” in any of these things. There is only seeing through to its virtues with the mind.


The heart of Emptiness is in the absence of anything with form and the inability to have knowledge thereof. Knowing the existent, you know the nonexistent. A warrior learns the way with certainty. He has no confusion in his mind and is never lazy. He polishes his mind and will, and sharpens the two eyes of broad observation and focused vision. He clears away the clouds of confusion. In Emptiness exists Good but no Evil. Wisdom is Existence. Principle is Existence. The Way is Existence. The Mind is Emptiness.

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