Please be punctual. When you come earlier, do warm-up exercises or practice by yourself or with others until Sensei comes. If you happen to be late, it is appropriate to ask permission from the instructor before entering the mat area (tatami).
While you practice, always be alert. Careless practice causes accidents and injury, and does not help you or your partner.
Leave socializing until after class, so as not to waste time or distract people during practice. It is even more important to observe well than to listen in Aikido, as you are learning movement, not mathematics.
Do not hesitate to let your partner and Sensei know when you cannot continue to practice because of sickness, tiredness, or whatever. When you really need a short rest, bow to your partner and sit quietly at the side of the tatami and watch the class. Your body belongs to you and nobody else, so take care of it and prevent accidents. If you must leave the tatami, notify Sensei before leaving.
For safety and comfort, keep your toe and finger nails trimmed, remove all jewellery, and empty your bladder before class. Most people will find they cannot eat a regular meal just before class and still do breakfalls. Keep your uniform clean, and if you sweat a lot, bring a towel or cloth to class. Do not drink water in the middle of practice; it is neither healthy nor polite.
In order to keep the tatami clean, always put on some footwear to wear on the way from the change rooms to the dojo, so that you will not track dirt from the halls onto the tatami. Do not wear shoes on the tatami. If you arrive early and notice dirt on the tatami, get a broom or mop and clean it up. It is customary to wash the mats prior to training seminars. If the mats are in disorder, have gaps between them, etc., push them together to prevent injuries during practice.
If you have to leave before a practice is scheduled to end, inform Sensei ahead of time and follow appropriate rei when leaving the mat area. Much can be learned even just watching a practice, so if you for some reason cannot practice, feel free to come by and watch.