There is an awful lot of local tradition connected with these two terms in aikido, and so perhaps there will be little consensus on a bulletin board such as this.
When I was a student in the UK and began to teach aikido classes at the main London dojo in the abence of Kanetsuka Sensei, no one ever used the term 'Sensei'. I suppose we would have been 'shidoin', but this is a descriptive term, not really a title.
And we never, ever used the term 'sempai' to refer to senior members of the dojo. This term is not really of the same kind as 'sensei'. In my university aikido club, there is a shihan, fuku-shihan, kantoku, and every single member is in a relationship of sempai or kohai to everyone else. The term 'sensei' is used only of people like myself, who are outside the club system. Similarly, in the city aikido dojo, neither 'sensei' nor 'sempai' are ever used, the chief instructor always being referred to as 'dojo-cho'. But this is the custom in Japan.
On the other hand, there is a custom (outside Japan in my experience) to refer to the person who teaches the class as 'sensei' and this happened at the recent Aiki Expo in Las Vegas. I do not have any real objection to this, but it is not a universal custom. In Holland, where I regularly instruct, I am known by my first name (as I am throughout the Aikikai) and 'sensei' is never used, even when I am teaching. This might be thought disrespectful, but I think that the quality of training is more important than the way you refer to the instructor.
Last edited by Peter Goldsbury : 05-31-2002 at 08:41 PM.