忘却心中 (Boukyaku Shinjuu)

Background
The song was first uploaded on October 18th 2007, and became one of Meiko's first hits (at the time of 2007, most notable songs are sung by Hatsune Miku; Meiko and Kaito didn't have as much hits) it was OPA's second work and became his most notable work. However, the video was taken down not too long after it reached 40,000 views. When asked, OPA stated he wasn't "satisfied" with the lyrics of the song. Later on, he read and fell in love with Asaki No'9's poem entitled Boukyaku Shinjuu.

The video was reuploaded on November 22nd 2007, with several tweaks, and reached 100,000 views on October 2nd 2008. OPA also released a singles featuring an "arranged" version of Meiko's Boukyaku Shinjuu available in Amazon.