Immediately following the 2017 Indy 500, I did a live painting of the winner in the Firestone hospitality chalet at the Speedway. As I was about to finish both Takuma Sato and team owner Michael Andretti came by to celebrate with us and sign the painting. Taku signed his name in traditional Japanese!
See a quick video: 
https://www.youtube.com/watch?v=y6stcDhdZTM
Note: I have a very few prints produced which were signed by Takuma.