[1] It is the theme song to the TBS drama series Ōoku: Tanjō - Arikoto / Iemitsu-hen, starring Masato Sakai and Mikako Tabe.

[2] "Deepness" was released close to five months after Misia's previous single, "Koi wa Owaranai Zutto".

[4][5] The single features the B-side "Koi Gram", written by Satoshi Shimano, as well as two remixes by DJ Gomi of the title track and of Misia's rendition of Michael Jackson's "Heal the World".

[7] She was struck by the female shōgun and all-male ōoku, and felt that the reversal of gender roles depicted in the manga was something modern women could relate to.

[9] The music video for "Deepness" was directed by Sayaka Nakane and shot in early October 2012 in the Mongolian grassland.

[20] "Deepness" peaked at number 10 on the Billboard Japan Hot 100,[21] making it Misia's seventh top ten entry on the chart.