Afterwards, he became a freelancer and established his own agency, Kensuke Office. The agency is run by Sasaki's wife (former Joshi wrestler), Akira Hokuto, and currently represents Sasaki, Katsuhiko Nakajima, Kento Miyahara, Takashi Yoshioka and Takashi Okita. Under the Kensuke Office agency, Sasaki and pupil Katsuhiko Nakajima toured other promotions, particularly All Japan Pro Wrestling and Pro Wrestling Noah.
In September 2006, Kensuke Office was announced as a member of the Global Professional Wrestling Alliance. Beginning in 2007, Kensuke Office has organised its own shows, and some of the talent featured on the shows include Minoru Suzuki, Jun Akiyama, Genichiro Tenryu, Yoshihiro Takayama, Kikutaro, Takeshi Morishima, KENTA and Catfish Man. Currently, Kensuke office serves as developmental territory of Pro Wrestling NOAH, featuring several of its superstars.
In January 2011, Kensuke Office was changed their name Diamond Ring.