KO-D Openweight Championship
In January 2006, he unmasked and started wrestling under the name Harashima. Together with Owashi and Jet Shogo (formally Shogo Takagi), they formed the heel stable Disaster-Box. In October, Harashima left the stable after being dissatisfied with the achievements of stable leader Owashi. On December 29, Harashima beat Owashi for the KO-D Openweight Championship. In 2007, he defended his championship against Daichi Kakimoto on January 28, Danshoku Dino on February 25 and Sanshiro Takagi on April 1, before losing it to Koo on June 3. Harashima regained the KO-D Openweight Championship on October 21 and made one successful defence against Yasu Urano on March 9, 2008. He lost the championship to Dick Togo in a 5-way match on May 6.