In an interview with Excite in February 2008, she revealed the melody of the chorus was actually from her second single, Tomorrow's Way, but she only wrote it halfway.

[1] Consequently, Yui tried not to put all the emphasis on "love", as was the main theme of 4 Shimai Tantei Dan, but on relationships between individuals as well.

The title, "Namidairo" (ナミダイロ), in Japanese literally means "tear-colored", but was officially translated as "the color of tears".

From thereon, the video cuts to Yui walking down a street or riding a bus alone, sitting in a telephone booth, or back to the room.

All tracks are written by YuiNormal Edition + DVD "Namidairo" has been certified gold by RIAJ for shipment of 100,000 copies in Japan.