In this article there is an intersting quote :
"Tomiki was unable to find a chance to break Ueshiba's balance with judo techniques when sparring with Ueshiba in the summer of 1927"
Of course we don't know the rules of "sparring", but we can suppose Tomiki was allowed to attack or sparr with Ueshiba with his judo skills.
I also suppose, Kano didn't send Tomiki to challenge Ueshiba, so Tomiki took the initiative himself to challenge Ueshiba and was very impressed by Ueshiba's skills. We can assume, Tomiki spoke later with Kano about his experiences.
Around 1930 Mochizuki was sent to Ueshiba.
There is another interesting quote :
Tomiki was affected by Kano's philosophical lectures during college. In 1927, soon after his graduation from Waseda University, Tomiki began practice with Morihei Ueshiba, later the founder of aikido. Tomiki was one of the first disciples of Ueshiba and was given the first 8th dan of aiki-budo by Ueshiba in 1940. Tomiki was in- quisitive and trained as an academic so he analysed the techniques of Ueshiba using the scientific principles that Kano invented. The event of the cause was Kano's en- couragement when Tomiki visited Kano with Takasaki at Kano's office at the Kodokan in March of 1936 to extend his regards to Kano prior to Tomiki leaving for Manchukuo. According to Tomiki, the following conver- sation took place between Kano and Tomiki [17, p.8]: • Kano: It is necessary for us to learn techniques that you learned from Ueshiba. But it is not easy to learn.
• Tomiki: If we study those techniques using the "Principles of Judo" or the scientific principles of judo that Master discovered, I think that it won't be impossible.
Just some thoughts,