This is from an interview with Shotokai Sensei Mitsusuke Harada, who trained with Gichin and Yoshitaka Funakoshi in the 1940s and Egami in the 1950s. Asked about his initial impressions of karate he says there were two main things - training at the Shotokan, and the kata Kanku-sho.
"I first saw the kata Kanku-sho at a local display and it was the jumping kick that impressed me. But unfortunately, at the Shotokan dojo, I had no opportunity to study it. When I joined Waseda University in 1948, in the first year I didn’t know all the kata but by the second year we had practised all of the designated Shotokan katas. But we never did Kanku-sho. So, I asked some seniors about this kata and although I did not know the name at the time, I remembered the jumping kick, which I described to the seniors. They then told me it was 'Kanku-sho'. But unfortunately I didn’t have any opportunity at that time to learn it. Then, in 1967, when I returned to Japan from Great Britain, I had the chance to learn Kanku-sho with the university (Waseda) group."
As a footnote to my blog entry on the history of the kata, it is interesting. Harada says he did not have the opportunity to learn the kata, but it was obviously around (we don't know who was doing the local display but the fact it had the 'jumping kick' does suggest it was the Shotokan version). Furthermore, he says that he did not learn it as part of the full 'designated Shotokan katas', though Gichin Funakoshi wrote that Kanku-sho was being taught at the Shotokan as of 1943 (coincidentally the year Harada began his training).
In Conversations with Karate Masters by Dr. Clive Layton (Ronin, 1988), Harada believes that Kanku-sho was one of the kata Yoshitaka brought back from Okinawa after his father sent him there in the 1930s. It's difficult to say how accurate this is, and I suspect it is not totally accurate, as basically his list of these kata consists of all but the 'core fifteen' (plus Taikyoku shodan).