Diana Hope (Grasshopper) wrote:
This may be different for different forms of aikido, but I've been told that in Aikikai, you only get to call someone "sensei" when they're yondan or higher.
Now, both my teachers (eek!) are sandan, and both encourage their students to call them by their names, what would/could one call "rank-wise"? Sempai?
In Japan (even in the Aikikai), whoever is teaching is routinely addressed as "sensei", whether they're a 4th dan or a 4th kyu. It's more an indicator of function than it is of rank.