"O"-正.反.合. is TVXQ's third Korean studio album, released on September 29, 2006. In a year when Korean music sales had slumped, it was the highest selling album in South Korea in 2006 which won the group several prominent awards in South Korea . It continues to chart and manages to stay in the top 50 each month. The album's name "O" - Jung. Ban. Hap is also the name of the lead single, which translates to "O" - Thesis. Antithesis. Synthesis or "O" - Justice. Opposition. Solution in English (some English articles also refer to it as "O" Union), in regard to global conflicts and a strong need for peace and resistance. The album has a balance of fast tempo songs and ballads.