Update: Saturday's session was a repeat session of Thursday with one hugely important difference: the first third was Isaka sensei's practice. We were also very happy because we have some guests over from France and I will post some photos soon(ish) ;
Because we had guests YS also went through basic movements showing IS movement into Kihon and Kumite. A lot of people just don't "get" Isaka Sensei's training, so there is nothing like seeing it being demonstrated by YS to see what's going on and why. YS regards Isaka Sensei training an essential component of his Karate and we all do benefit from it.
(Below: Ohtsuka Sensei and Shirakawa Nomikai Shihan in IS training)
I can see three major reasons why people don't "get" IS training:
a) It's counterintuitive; how can you be fast if you train so slow?
b) It's actually very, very, very difficult to do properly and it's very, very, very easy to cheat
c) Many Shotokan karate people rely on "snap" and handspeed and have lost (or in so many cases are completely clueless) about getting their weight and body behind a technique- which is why training the heavy bag is so useful, right!)
I will try do address these points soon; but it's Sunday afternoon I have to cook dinner for Yuko now so it's going be absolutely delicious ;-)