Personally, I try not to get too bogged down in definitions. They are only signposts, symbols, and approximations for the actual. I agree with Kevin in his analysis on BJJ with centerline. And I do think that what I was doing was sankyo, by my definition. In fact, you can see me submitting one of my students with it here
, about 3/4 of the way through, in slow motion. It's sankyo to me, although others would simply refer to it as a wristlock.