2000, Tamura partaked in the King of Kings tournament as well, eliminating Zaza Tkeshelashvili before going against another Brazilian, Antônio Rodrigo Nogueira. The jiu-jitsu expert opened the match taking Tamura down and trying to pass his guard, eventually performing an armbar which Kiyoshi countered rolling outwards and taking his back. The Japanese fighter then avoided a kneebar and attacked Nogueira's guard until the standup. The action repeated itself, with Nogueira taking him down and Tamura capitalizing on a kneebar attempt to get dominant position, but this time Nogueira reversed and attempted a Kimura lock for the end of the round. At the second one, the Brazilian pressed Tamura with a takedown and slowly climbed up his way through positions to an armbar from the back. Kiyoshi defended it for minutes, but at the end, Nogueira repositioned and got the hold, making Tamura tap out. After his King of Kings tenure, Tamura was granted a rematch against Renato Sobral, but as in the first time, the bigger Brazilian controlled the bout with wrestling and positional dominance. Kiyoshi had his last fight for RINGS facing Gustavo Machado, losing an uneventful decision again. PRIDE Fighting Championships Tamura made his debut in PRIDE Fighting Championships in a title fight against Wanderlei Silva for the PRIDE Middleweight Championship. Silva blocked Tamura's takedowns and attacked him with hard punches and a knee to the face. In one instance, Tamura landed a punch which stunned Wanderlei, but it was short-lived, and the Brazilian fighter recovered and continued with the brutal ground and pound, bloodying Kiyoshi's face. The second round saw the same action, with Silva counterstriking with a right hook which knocked out Tamura for the win. After the bout, there were suggestions for Tamura to portray the Tiger Mask professional wrestling gimmick in the Pride ring, having his first match against Ryan Gracie. However, those plans were abandoned. Tamuras next match would be a similarly tough matchup, facing the large Bob Sapp, who almost doubled Tamura's weight. The match was short and shocking, and saw Sapp charging at Tamura and knocking him out with looping punches at 0:11. At PRIDE 31, Tamura got a desired rematch against Antônio Rodrigo Nogueira, who had bested him years before in RINGS. The result would be the same, as Nogueira took him down, gained his back and locked an armbar for the tap out. In an event for related promotion