IU's 3 octave song, "Good Day" is expected to be a hit in Japan. SBS's 'Fighting Japan! Seoul - Osaka Music of Heart' (hosted by IU, Sulli, Lee Hong Ki, and Lee KiKwang), aired earlier today on June 27th, where IU performed her hit song, "Good Day". IU has yet to officially start her career activities in Japan; instead she had just performed in different shows in Japan from time to time. However, despite the limited special activities she had participated in, many fans gathered at the Kyocera Osaka Dome to see her perform proving it to be highly likely that her 3 octave high song will work in in Japan as it did in Korea. Meanwhile, TVXQ, 2PM, 4minute, 2NE1, IU, MBLAQ, U-KISS, FT Island, B2ST, f(x), T-ara, and Rainbow also performed at 'Music of Heart'. Source & Photo: Newsen