Thought I'd offer a few thoughts on the opening of the class for some beginners or even seasoned vets, who can easily train for many years without being privy to this information.
To clarify; as long as you show the proper respect through the bows and patience to your instructor and the Shomen, then etiquette is served. However that is not the extent of our opening at the Shudokan Black Belt Academy.
Most Yoshinkan Dojo have a very simple opening, whereby the students line up in wait for the instructor. This is done in the seated position. once the instructor is seated the Dojo 'captain' calls the bows to Shomen and then to the Sensei. Then training begins.
At SBBA we have a slightly different approach. I am given to understand that this comes from Soke Eddie Stratton's personal study with other schools, and also of Zen meditation (it is worthy of note that he was good friends with, and the Aikido instructor of Tony Doubleday, co-author of 'The Elements of Zen' [read it]).
So, like all our practises, this is a legacy. Therefore, like all our practices, it is important to understand the process. For what it's worth then, here's my understanding of it;
It is good etiquette, but not widely practiced, to perform a seated bow when stepping on the mat for the first time and stepping off for the last. After the warm up the assistant instructor should call 'line up' or something similar. In our dojo, which is long and narrow, we create multiple lines structured quite militarily. This is the first difference between us and other Dojo of Yoshinkan lineage.
The assistant calls 'Seiza Ho, Seiza!', which means '[using the] sitting method, sit'. For assistants it's worth taking note here that the command is 'sit' and not 'method', so 'Seiza, Seiza Ho!' doesn't make sense as a command and emphasising 'Ho!' sounds good to the English speaker but probably silly to Japanese.
Once sat, the assistant calls 'Shomen Rei' ('bow to front wall' where the pictures of past [and notably passed] instructors are, out of respect) and then once the instructor has turned; 'Sensei ni Rei' ('bow to the teacher' who reciprocates). You may notice people shouting 'Osu' during these bows. It's not necessary but is good etiquette to say this to the instructor, I don't think it's correct to shout 'Osu' at the wall, which cannot shout it back.
Meditation and Clapping(?!)
Then the instructor turns back to the Shomen. Here he may say some more Japanese. Some instructors shout simply 'Misogi', which means 'cleanse' but I like to add 'Mokuso' ('mok-so') which means 'eyes closed'. This is to initiate the meditation which I will walk you through.
If you don't give a monkeys about the spiritual aspects of training (which I totally get) then please understand that when I talk about Zen, and feelings I am merely describing a physical practise that is difficult to describe without such analogies and metaphors. I have found over the years that 'Ki' is revealed to be a true combination of timing, distance and balance and not a mythical and magical force at all. However to get to that point I had to allow myself to (at least partially) buy in to certain paradigms and beliefs. These are just part of the path.
The hands should be in Za-Zen. The fingers of the left hand laid atop the right, with the thumbs touching, in front of the belt knot. It is important to have a straight back. The right big toe should be laid just over the left. I believe the theory is that this creates a circuit.
The breathing is similar to Yogic breathing. In through the nose and out through the mouth. The first three breaths are the 'mosogi' bit. Start off by breathing out fully. We make the sound 'ar' with the breath so we know when it is at its natural end.
To breathe in, place the tongue on the roof of your mouth and draw the breath in through the nose by pushing the stomach away from the spine, thus opening the diaphragm. Do not suck from your throat, or sniff. Repeat this process twice more, ending on the inward breath. Then continue to breathe normally, in through the nose and out through the mouth.
The end of the meditation is signalled by two claps. This is an old tradition from O'Sensei, which is ostensibly spiritual but actually I find it triggers important responses from my sub-conscious. By the end of the second clap, you should be mentally prepared for training. If you can get your head around that, soon you won't need it any more. I still like it.
I hope that for some of you this has disambiguated an area that is often glossed over to get to the 'good stuff'.