Hi Des, Thanks for getting in contact with me on Twitter. Yay for the internet. I can add that in our karate dojo in Brisbane, Australia the most senior student is referred to as the Jokyo. Our instructor is James Duggan Shihan (Shihan is given at the 5th dan in the Goju Ryu and Goju Kai system) and 3rd dan is referred to as Sensei. As a 1st dan I am a Sempai which I translate as apprentice or someone who is aspiring to be a Sensei but still needs to do some more time learning and developing their teaching skills. We also have Kohai who are the senior students that have completed their Black Gi Grading... That last bit about the Kohai is a non standard formality but works well in our dojo as the Black Gi Grading is a torrid journey and Kohai as a senior rank doesn't just reflect their rank but their achievements.