Kamen feat. Tatsuya Ishii (仮面 / Mask) (stylized as KAMEN feat. 石井竜也) is the tenth single of Koda Kumi's 12 Single Collection and featured Kome Kome Club's frontman Tatsuya Ishii. Like many of the other singles released in the collection, KAMEN is also limited to 50,000 copies. The song debuted at #3 on Oricon and charted for six weeks.

Kamen feat. Tatsuya Ishii is Japanese singer-songwriter Kumi Koda's tenth single in her 12 Singles Collection. It featured Tatsuya Ishii (also known as Tatuya Ishii) from the famed group Kome Kome Club, who had written the lyrics to the song, alongside composer Kazuhito Kikuchi. At the time, Kazuhito Kikuichi had just separated from the rock duo Breath. As with most of the other singles in the collection, the single was limited to 50,000 copies.

Unlike usual singles, Kamen feat. Tatsuya Ishii carried three different karaoke versions of the title track: one for men, one for women and a full instrumental. The "with your darling version" omitted Kumi's voice, but kept Tatsuya's. The "with your honey version" omitted Tatsuya's voice, but kept Kumi's. The final track was the full instrumental, omitting both artists' voice.

Though limited to 50,000 copies, Kamen feat. Tatsuya Ishii still managed to sell 46,971 copies as of 2006.

"Kamen" feat. Tatsuya Ishii was not part of the story-themed music videos.

The music video carried a Phantom of the Opera theme, but with the female lead, played by Kumi, falling in love with the masked man, reciprocating the Phantom's love and affection. The video carried many visual themes that Kumi would later use in her videos for Unmei and Aishou.

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