10 Longest Reigning IWGP Heavyweight Champions Ever
10. Kensuke Sasaki - 279 Days
Genichiro Tenryu is a true legend of Japanese professional wrestling (not to mention one with an undefeated WrestleMania record) so it will come as somewhat of a surprise to learn that Mr. Puroresu only held the IWGP Heavyweight Championship on one occasion. Tenryu was the champion heading into the new millennium but he lost the title in his first defence of the new century in the main event of the 4 January Tokyo Dome show to Kensuke Sasaki.
Sasaki wrestled that match with a 39 degree fever but still managed to overcome the legend Tenryu, before going on to defend the belt on five occasions, beating Don Frye, Satoshi Kojima, Great Muta, Manabu Nakanishi, and Takashi Iizuka.
Sasaki's reign (his second with the title) came to an end in strange circumstances after 279 days. Sasaki was defeated in a non-title match by Toshiaki Kawada at a New Japan vs. All Japan event, and the championship was vacated as a result. To make the entire thing redundant, Sasaki regained the title in a tournament, defeating Kawada in the final.
Kensuke Sasaki was the only man to hold the IWGP Heavyweight Championship between 4 January 2000 and 17 March 2001, but the fact that his reigns were broken up means the two-time G1 Climax winner's longest title reign is good enough only for 10th.