Osu is the one word that you'll hear the most in a Kyokushin dojo or at a Kyokushin tournament. When you enter or leave the dojo, you bow and say "Osu". When you greet a fellow Kyokushin Karateka, you say "Osu" instead of "hello". When you respond to an instruction or question in class, you say "Osu" instead of "yes" or "I understand". But what does it really mean ? It means patience, determination and perseverance. Every time we say "Osu", we remind ourselves of this.