As far as the higher ranker on the one side of the dojo goes, it isn't always that way. We were doing partnered forms with thw swords and whoever was next to sensei would be doing the same thing as him and the other two people on the other side of the dojo would be doing the other half. Evidently, by me going and standing next to sensei, that put me in the sempai spot because they were defending and the person on the other side would be attacking shomen. I get just about everything except sempai and kohai for people of the same rank... it is a bit confusing!
And from the discussion above, you also should have got that the sempai / kohai relationship does not extend to having 'spots' in the dojo when you do paired weapon practice. When I teach the 31-jo awase, it is easier initially to split the dojo members into two groups, with one side of the dojo doing uchi
and the other side doing uke
. However, the persons standing closest to me do not thereby become sempai to the other members. They might indeed be sempai, but they will be sempai for other reasons.
Having seen this and other similar discussions on Aikiweb, I have the impression that some teachers / dojos outside Japan invest more into the concept of sempai/kohai than we do here. I am not stating that this is wrong--just pointing out the difference. Dave Lowry has been mentioned above and in his book In the Dojo
, he has a discussion on sempai/kohai pp.168-173. But he also includes another, separate discussion, on the roles of defender and attacker in the dojo. The entire chapter (Chapter 12, The Student), is worth reading. Lowry is very careful in this chapter, but he occasionally states things that do not quite square with my own experience here. It is not that he is inaccurate; simply that even in different arts / dojos, there are some aspects that are emphasized more than others.