Rock A Japonica

 is a Japanese girl idol group managed by Stardust Promotion. It was formed in 2015 with five members from 3B Junior (out of 26 in total):Ami Uchiyama, Luna Naitō, Ruka Shiina, Chiho Takai, and Misato Hirase.
The name of the group implies their intention to "rock Japan" (to shake it, impress, get it going). 
The group was dissolved on April 29, 2019, but will have one more performance during the "EVIL A LIVE 2019" festival.
The 3 remaining members came back with the new unit B.O.L.T on April 15, 2019