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. The home version of 4thMix was released in Japan on March 15, 2001, for the Sony PlayStation console. It contains 55 songs, including 3 from Dance Dance Revolution 3rdMix (which were not present in the home version of that version) and six hidden songs: one from 4thMix Plus and one as preview songs for the next arcade version, Dance Dance Revolution 5thMix. The game also features the 6-panel mode, branded as Solo Mode.