Dance Dance Revolution 4thMix, or 4thMix, is the 4th game in the main Dance Dance Revolution series of music video games. It was released as an arcade game by Konami on August 24, 2000. Although only officially released in Japan, units exist worldwide. 4thMix features 136 songs, 49 of which are new to this mix. Twelve of the songs are initially hidden and must be unlocked by the arcade operator. 12 songs are unlockable in 4th Mix Plus, giving them 150 songs in total. In DDR 4th Mix, new songs that first appears in DDR 3rd Mix Plus, DDR 3rd Mix Korea and DDR Solo appears in this mix.