Kara once again witnessed their popularity in Japan, as their guerilla concert in Tokyo had to be stopped due to the great number of people who attended. After releasing their Japanese debut single, Mister, on the 11th, and reaching number 5 in Oricon charts, Kara held a guerilla concert at Tokyo's Shibuya 109 mall as part of their debut event. Although this event was not officially announced, 3,000 fans who heard the news, all of a sudden gathered to watch Kara perform. As soon as a greater number of people than expected arrived for the concert, Kara's Japanese management company, Universal Japan Sigma, had to suspend the concert in 3 minutes when it was supposed to last 30.   KARA was scheduled to take photos with fans, have a brief Q&A session, and perform some songs.  However, because the fans were over reacting and created a panic, they had to unfortunately cancel this surprise event after performing just one song.  The reason for this was because the location of Kara's concert was a famous traffic area in Tokyo, and the massive gathering of the crowd could be dangerous for the peoples' safety. Multiple Japanese news media, including Sankei Sports, has reported this unbelievable event, and once again confirmed Kara's successful debut in Japan.