Tone is the fifth Japanese studio album (tenth overall) by South Korean pop group Tohoshinki, released on September 28, 2011 by Avex Trax. It is Tohoshinki's first Japanese album since becoming a Duo, with members Yunho and Changmin. Tone was released in three physical versions – Version A, a CD+DVD version with music videos; Version B, another CD+DVD version with off-shot movies; and Version C, a CD only version with a bonus track. Composing sessions for the album began in 2009, bull full production began in early 2011. The album was a major commercial success: it was Tohoshinki's second album, but first original release, to top the Oricon Albums Chart, selling 205,000 copies on its first week of release. Earning a platinum certification by the Recording Industry Association of Japan (RIAJ) two weeks later, Tone eventually became Tohoshinki's best-selling original Japanese studio album, with over 330,000 copies sold. On September 27, 2011, the first day of album release, Tone topped the Oricon Daily Album Chart at first place by selling 105,484 copies, surpassing their previous studio album The Secret Code's first day sales of 82,891 copies, the album maintained the daily #1 rank for the remainder of the week. On October 4, 2011, Oricon reported that Tone has sold over 204,980 copies for the week of 9/26~10/2, again surpassing The Secret Code's first week sales of 157,954 copies; it ranked first on the Oricon Weekly Album Chart and earned Tohoshinki their first weekly #1 rank for a studio album release.This is also the first time in over 11 years that a foreign male artist has sold over 200,000 copies in the first week since Bon Jovi's Crush.On November 7, 2011, Oricon reported that Tone has sold over 278,057 copies for the month of October, topping the Oricon Monthly Album Chart at first place, making this the first time Tohoshinki has achieved the monthly #1 rank with a studio album release. On October 7, 2011, Tone was certified Platinum by the Recording Industry Association of Japan (RIAJ) for shipping over 250,000 copies. On December 19, 2011, Oricon reported that Tone has sold over 293,674 copies in 2011, ranked 20th for the year on the Oricon Yearly Album Chart. It reached #1 Billboard Japan Top Albums and #1 Gaon South Korean International Albums Chart.
"I Think U Know" was co-written and produced by Dsign Music.