Who was Miyamoto Musashi?
Miyamoto Musashi is considered one of the most influential samurai of all time. He is the greatest swordsman who remains undefeated even after sixty duels. People also claim that his whole life he had scorching ambition and an impenetrable focus. After the battle of Sekighara, Mushashi became a ronin ((in feudal Japan) a wandering samurai with no lord or master.) Aside from being a swordsman, he was also a philosopher, an artist, and a well-learned Buddhist.
Before, passing away, Miyamoto Musashi left a series of 21 written pieces of principles (timeless rules or guidelines) known as Dokkōdō.
These written pieces of his works reveal that his lifestyle revolved around discipline, sacrifice, restraint, and having so much self-control to not become impotent by an endless stream of pleasures.
His words are not a random motivational YouTube Horse-Manure. No, rather a series of lifelong lessons. Lessons that are acquired only by having immense focus and concentration their whole life.

The 21 principles of Dokkodo:
1. Accept everything just the way it is.
2. Do not seek pleasure for its own sake.
3. Do not, under any circumstances, depend on a partial feeling.
4. Think lightly of yourself and deeply of the world.
5. Be detached from desire your whole life long.
6. Do not regret what you have done.
7. Never be jealous.
8. Never let yourself be saddened by a separation.
9. Resentment and complaint are appropriate neither for oneself nor others.
10. Do not let yourself be guided by the feeling of lust or love.
11. In all things have no preferences.
12. Be indifferent to where you live.
13. Do not pursue the taste of good food.
14. Do not hold on to possessions you no longer need.
15. Do not act following customary beliefs.
16. Do not collect weapons or practice with weapons beyond what is useful.
17. Do not fear death.
18. Do not seek to possess either goods or fiefs for your old age.
19. Respect Buddha and the gods without counting on their help.
20. You may abandon your own body but you must preserve your honor.
21. Never stray from the Way.
Accept everything just the way it is.
Call me biased, but, all the 21 principles are filled with eternal wisdom. You might be true, and we might argue. There can be a case made for all of these principles that these all rules might be applicable in one’s life but not in others.
However, the first rule ─ “Accept everything just the way it is” is the only rule one could not argue upon.
In fact, I think that it is the only rule that can be certainly applied to every single human being.
Take your life for instance, whenever you have a bad breakup your mind and body are in a constant denigration state and there is an ongoing war against your beliefs, thoughts, and actions. Your mind is not ready to accept the fact that the person you once loved the most has passed away(in a metaphorical sense in the case of a breakup). The person you once thought could and would remain with you; from the beginning to the very end of your life is now gone. Gone to a place from where he/she cannot be resurrected.
In brief, you are in ‘Denial’. A state of mind where you have to negotiate with yourself that reality is here and now. Not the way it previously was.
Anger after Denial
But, the process of dealing with reality doesn’t just stop there. After convincing your mind that reality is not what you thought it was, the mind (or you) becomes angry. As you are infuriated against the world for not functioning as the way you want it to function. After all, not realizing that it was you who thought so highly of the world.
Consequently, the next stage comes after Denial and Anger and that state is ‘Depression’
This is the third stage in the way of overcoming grief. And in this stage, you stop revolting against the world and start looking within.
Bargain with Yourself
Now, you realize something. Something extraordinary. To conclude, you understand that it was never the world that’s been untrustworthy. It was you. It was you from the beginning who was dishonest, not against the world, but to yourself. You never talked to yourself. Never bargained even. All you did was ─ constantly be a tyrant toward your own self. Keeping your mind hostage and your thoughts in captivity of it. Once you bargained with all these tantalizing thoughts. Then you start to realize what lessons Miyamoto Musashi taught through his texts.
Acceptance ─ “IT IZZ WHAT IT IZZ.” ─MIYAMOTO MUSASHI
Acceptance is the first rule that Miyamoto Musashi taught.
The phrase “it is what it is” refers to an irritating or difficult circumstance that a person feels cannot be altered and must just as well be accepted.
You can only alter reality through the things that you have control over. The circumstances you cannot control can and will most definitely strain your focus. So, to summarize, one must always accept reality just the way it occurs. Do not try to perceive reality through a lens of your own thoughts or feelings. Chances are you might as well corrupt your way of thinking and having perspectives. Moreover, what’s even truer is the fact that Miyamoto Musashi even as the best Samurai ever to be born never let his thoughts (or feelings, for that matter) corrupt his way of perceiving reality. This might be the reason that he became the best swordsman of all time.
He not only accepted reality the way it was, but also he acted upon it accordingly. Simultaneously, makes him the most skilled warrior and wise philosopher at the same time.