Final answer:
The common rule for dojos is to show respect for all, in line with their tradition of discipline and courtesy. This is part of the culture of combat sports and ensures a respectful environment.
Step-by-step explanation:
The common rule found for dojos, as described in the question, would be to show respect for all. Dojos that teach martial arts uphold a strong tradition of respect, which is evident in how competitors act towards each other. For instance, after a judo match, as depicted in the provided example, it is customary for opponents to display respect towards each other through gestures such as bowing or shaking hands. This practice of showing courtesy, concern, and respect is not only part of the dojo rules but also ingrained in the broader culture of combat sports, even at the professional level in boxing or mixed martial arts. Options such as eating in the dojo or loud talking would typically be discouraged as they can detract from the disciplined and respectful environment that dojos strive to maintain