The 20 Precepts [Niju Kun] or Guiding Principles of

Gichin Funakoshi Sensei.

Karate-do begins with courtesy and ends with rei.
There is no first strike (attack) in karate [either mentally or physically] - “Karate ni sente nashi”
Karate is an aid to justice.
First know yourself before attempting to know others.
Spirit first, technique second.
Always be ready to release your mind.
Accidents arise from negligence.
Do not think that karate training is only in the dojo.
It will take your entire life to learn karate, there is no limit.
Put your everyday living into karate and you will find "Myo" (subtle secrets).
Karate is like boiling water, if you do not heat it constantly, it will cool. (qv: also by Tsunetomo Yamamoto)
Do not think that you have to win, think rather that you do not have to lose.
Victory depends on your ability to distinguish vulnerable points from invulnerable ones.
The out come of the battle depends on how you handle weakness and strength.
Think of your opponents hands and feet as swords.
When you leave home, think that you have numerous opponents waiting for you.
Beginners must master low stance and posture, natural body positions are for the advanced.
Practicing a kata exactly is one thing, engaging in a real fight is another.
Do not forget to correctly apply: strength and weakness of power, stretching and contraction of the body, and slowness and speed of techniques.
Always think and devise ways to live the precepts of karate-do every day.