January 10, 2011, the group released their third single "Chime! / Doshaburi Regret". Narumi Uno departed the same day. It was announced on February 21 that Hinaki Yano would depart from the group, and her final performance would take place on March 20. However, due to the 2011 Tōhoku earthquake and tsunami, her departure was postponed to April 17. On April 27, the group released their 4th single "The Tissue ~Tomaranai Seishun~". Rio Koike announced through a blog post on June 7, that she would be departing from the group to focus on her education. In June, it was announced that Ebichu was to hold their first solo concert, on October 8 at Shibuya O-East. Parts of it were released on the band's first live DVD, which was released on February 15 of the next year. In total, Ebichu gave three sold-out performances in October. Two more singles, "Oh My Ghost? ~Watashi ga Akuryou ni Nattemo~" and "Motto Hashire!!", were released in July and October respectively. Reina Miyazaki announced her departure from the group in December. This would be Ebichu's last lineup change for several years. As of March 2012, there were nine members and the only two original members who still remained in the group were Mayama and Mizuki. Although in April 2012 they both entered high school, it was decided that they would remain in the group. They started joking that they were middle school students forever. Major label debut and Chunin (2012–2013) After six "indie" singles on their talent agency's recording label, the latest few of which charted on Oricon, the group signed a temporary contract with the major label Defstar Records to release a single titled, incidentally, "Karikeiyaku no Cinderella" ("Temporary Contract Cinderella"). The release date had already been determined as May 5, 2012, the Children's Day. The contract signing was made into a ceremony, which was held on March 4 in the presence of a large audience of fans. The single "Karikeiyaku no Cinderella" debuted at number 7 in the Oricon daily ranking for May 1. Having peaked in the daily chart at number 2, it also debuted at number 7 in the Oricon Weekly Singles Chart. From March 11 to May 20, Ebichu embarked on their first major tour, titled "Shiritsu Ebisu Chugaku Spring DefSTAR Tour 2012 ~Korya Haru kara Ebi ga ii!~", totaling 26 performances. On June 25, 2012, Shiritsu Ebisu Chugaku performed