Yey Congrats our dear Hyun Joong! Though I still dont have your album hehehe. But anyway, Im happy for HEAT's success!
Credit: blog.daum.net/elley0606
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He has received the 'Gold Disc' award for July 2012 under 'Singles' category with 2nd Japanese single 『HEAT(히트)』.
It is awarded by the Japan Records Association when a discography has a sales of more than 100K copies.
Source: http://media.daum.net/entertain/enews/view?newsid=20120813084209410
Source 2: http://www.diodeo.jp/magazine/magazine_view.php?ma_num=1483&ma_gubun=3&selmenu=5