series, Dragon Ball Z stating "The Z in our name is a very obvious reference to Dragon Ball Z" and that "It's a awesome and very influential series". Momoiro Clover Z's first single after Hayami's departure was "Z Densetsu: Owarinaki Kakumei", accompanied by a new group image and stage performance. The girls wore outfits with helmets and so-called "transformation belts" reminiscent of Japanese superhero movies, and the music video also borrowed from such "Super Sentai" imagery. In July, Momoiro Clover Z released their first album, Battle and Romance. Later in December, Hotexpress described the band as the number-one breakthrough idol artist of 2011 and stated that the album became a big turning point for them. Next February, Battle and Romance won the Grand Prix at the CD Shop Awards as the best CD of the year selected by music shop employees from all over the country. Momoiro Clover Z was the first idol group to win the award. On Christmas Day, 2011, Momoiro Clover Z gave a concert at Saitama Super Arena to their biggest audience to date: all 10,000 tickets were sold out. 2012: Rising popularity in Japan In May 2012, Momoiro Clover Z performed in Putrajaya, Malaysia. The former Prime Minister, Najib Razak, personally greeted the group. In June, Momoiro Clover Z opened a national tour, which closed with a sold-out show at Seibu Dome in August to a capacity crowd of 37,000 fans. Both dates were broadcast live to selected cinemas across Japan, the latter also to Taiwan and Hong Kong. The group recorded an ending theme song for Pokémon's Best Wishes series (titled "Mite Mite Kocchichi" and included in the eighth single "Otome Sensō" as a coupling track). In July, Momoiro Clover Z performed at Japan Expo 2012 in Paris. Momoiro Clover Z's ninth single "Saraba, Itoshiki Kanashimitachi yo", which appeared in November, topped the Billboard Japan Hot 100 chart, becoming their first single to do so. On December 31, Momoiro Clover Z performed at Kōhaku Uta Gassen, an annual New-Year-Eve music show hosted by NHK, for the first time. Going to Kōhaku had been the group's goal for a long time. During the January 1 Ustream broadcast, Momoiro Clover Z made several announcements: that the band set a new goal for itself — to give a concert at the National Olympic Stadium, an arena with 60–70,000 capacity, that they would release a new album in