Musashi's thoughts were, "Since we are born and live on this earth we should face God, give birth to children, increase the human race and make those around us happy. In order to do this we have to face the unavoidable and our fatality, our meaning of life. We use the term Shukumei wo motteiru. meaning 'To understand what we are born with'. The strength to face fatality is called Bu by Musashi. Bu means an honest feeling and an honest heart. This honesty is based on thoughts of God.
Musashi also used the word Chokudo. This means "To take straight path". Lots of people try to persuade you will lessons of what you should do in life. Musashi said, "If you just listen and dont take action it means nothing".Buddha preached his Buddhism but did this make India happy? Look at the country now. The same can be said of Jesus Christ. What are the Jews doing now? Musashi put his strength into the mening of life which is greater than his fatality and he called it his Bu. His name starting with Mu has the same meaning.
"An honest feeling, an honest heart". Musashi's waza is "empty" without Musashi's Mu.