That teacher was Ueno Takashi, not Tanemura. You're getting very mixed up there. And as far as Ueno Sensei being Takamatsu's student, there is a fair bit of contention there. Hatsumi always used to describe him as such, but other sources all indicate that they were more colleagues who shared information than teacher and student (ie Takamatsu got as much from Ueno as Ueno got from Takamatsu). You're also getting a little confused with Tanemura leaving the Bujinkan, by the way. Where you're coming from is Takamatsu apparently was sending letters to Tanemura as well as Hatsumi, and indicated to Tanemura that he should be the one to take over from Hatsumi as the 35th Head of Togakure Ryu. When Hatsumi became ill in the early 80's and didn't hand over the Sokeship, Tanemura did feel a bit put out. But that is not the reason he left (although it is possibly a reason he sought out so many other students of Takamatsu upon leaving).