What stage did Sayaka Onuki 大貫彩香 go to the theater?

Sayaka Onuki 大貫彩香updated Instagram on August 11,2019.  Sayaka Onuki 大貫彩香revealed that he went to the stage theater.  It is said that Sayaka Onuki’s play was a school comedy work by Riki Shirayagi,“Isn’t Boys Hard?”