If you have ever been to other karate clubs and/or demonstrations, you may have heard the students and instructors use the term Oss. Oss, or Osu as it was originally spelt, is a general term that all karateka say to a Sensei after they have finished speaking or demonstrating in a class. The term Oss is pronounced “Us”. The phrases "I understand", "please", "yes", "sorry" and "thank you" are some of the things that this one term can mean.
Saying Oss, should be done in the same way a Kiai is made. Not from the throat but from the abdomen and felt from the heart. It should be spoken with passion and feeling. Saying this term with meaning and feeling help greaten your focus on the technique at hand, whatever it maybe. It should drive your spirit, allowing you to perform better.
Not all karate clubs say Oss or Osu. This is not a problem, as most clubs will use standard words for "yes", "thank you", "please", "I understand" etc.