Jun Kasai
On February 21, 2016, Ibushi announced that while he had been cleared to return to the ring from his herniated cervical disc, he had decided to resign from both DDT and NJPW and continue his career as a freelancer due to feeling he could not handle the burden of working two schedules. As a freelancer, he is billed as a representative of Ibushi Puroresu Kenkyujo ("Ibushi Pro Wrestling Research Institute"). He wrestled his return match and his first match as a freelancer at DDT's 19th anniversary event on March 21, where he and Gota Ihashi defeated Jun Kasai and Sanshiro Takagi, and Kenso and Michael Nakazawa in a three-way tag team match. In April, Ibushi returned to the United States to take part in events held by Evolve and Kaiju Big Battel, while also appearing in the audience at WWE's event. On May 29, Ibushi made his debut for Inoki Genome Federation (IGF), defeating Tanomusaku Toba. On August 11, Ibushi made his debut for Wrestle-1, defeating Jiro Kuroshio.