Judo originated in Japan and it preserves many Japanese customs including the practice of bowing (rei). Bowing is a sign of respect and gratitude in Japan and people bow when they meet, when they are thanking someone, when they are apologizing, and at numerous other times.
Two major types of bow are customary in judo: a standing bow (ritsurei) and a more formal kneeling bow (zarei).
The standing bow begins from a position of attention with body straight, hands at sides, and heels together. Bend your upper body forward from the hips approximately 30 degrees and pivot your hands slightly to the front of your legs above the knees. Hold the bow for a second or two and then return to attention.
When we are lined up at the beginning or end of class or we are waiting, judoka often sit in a formal Japanese way. This kneeling position of quiet alertness is called seiza. You need to sit on, not between, your feet - this can take a bit of practice, so don't be worried if you don't get it right away - with your body straight but relaxed.
The kneeling bow begins from the seiza position. Your body should be relaxed, but not slouching, and your hands should be at rest on your upper thighs with your elbows slightly flexed. When the command is given, you slide your hands to the floor and form a triangle between your hands and thumbs (we'll show you in class!). Lower your head, trying to keep the top of your back horizontal, until your forehead is a few centimeters from the floor. Do NOT rest or bang your head on the floor.
In our club (dojo) we perform a standing bow when we enter or leave the room and again before we step onto or off of the mat. This shows our respect for the training hall and for the people in it. We also line up and bow at the beginning of each class. This is most often a kneeling bow, but it can be done standing. The students and instructors turn and bow towards a picture of the founder of Judo, Dr. Jigoro Kano, as a mark of respect and as thanks for having created our sport. The students and instructors then bow to each other; the students thank the instructors for teaching them and the instructors thank the students for learning.
While we are practicing it is traditional to bow to each partner before and after working with them. Mutual respect is one of the fundamental lessons of judo.