Morning Musume '15 Sayashi Riho & Sato Masaki Birthday Event (モーニング娘。'15 鞘師里保＆佐藤優樹 バースデーイベント) is a DVD featuring the birthday events of Morning Musume '15 members Sayashi Riho and Sato Masaki, which both occurred during the month of May. The deadline to pre-order the DVD was on July 27, 2015 and was for Fanclub members only.