As it is March 15th in Japan as of the writing of this post, today is Uni Sonoda's Birthday! Umi is a pragmatic and serious girl with a strong will, but is also pretty shy. As a result she tends to avoid being adventurous or trying new things, instead sticking to the 'traditional' method. Joining μ's helped her understand the purpose of trying new things and made her more rounded as a person. She is also a member of the school archery club! Happy Birthday Umi-chan!!
Just like with all the μ's character's birthdays, if you log into School Idol Festival, you will get 5 Loveca stones (Love Gems in non-Japanese versions).
Top Image Source: 根岸千秋＠ティア116参加予定 Pixiv