The first performance of Sinfonia Concertante is on 17 May! Tickets are available here. Here is the publicity flyer.
Here is an interview with the soloists, with excerpts from the cadenza.
Watch my video message (in Japanese).
YouTuber naco-san introduced the concert in her live-stream on 18 April (watch from about 02:11:00. I also make a brief appearance at around 02:17:30!