On June 16 at Dominion 6.16, Tanahashi defeated Okada in a rematch to win the IWGP Heavyweight Championship for the sixth time, tying Tatsumi Fujinami's record for most reigns with the title. Tanahashi made his first title defense on July 1, defeating Togi Makabe at an event co-promoted by New Japan and All Japan. All reigns combined, this was Tanahashi's twenty-first successful defense of the IWGP Heavyweight Championship, which was another New Japan record. Tanahashi made his second successful title defense on July 22 against Masato Tanaka. The following month, Tanahashi took part in the 2012 G1 Climax tournament, where he won five out of his first seven matches, but a loss to Karl Anderson on the final day of the tournament caused him to narrowly miss advancing to the finals. On September 23 at Destruction, Tanahashi successfully defended the IWGP Heavyweight Championship against Pro Wrestling Noah's Naomichi Marufuji, avenging a loss suffered during the 2012 G1 Climax. On October 8 at King of Pro-Wrestling, Tanahashi defeated Minoru Suzuki for the fourth successful defense of his sixth IWGP Heavyweight Championship reign. The match received rave reviews, including a five-star rating from Wrestling Observer Newsletter's Dave Meltzer. On November 11 at Power Struggle, Tanahashi made his fifth successful title defense against Yujiro Takahashi. Later in the month, Tanahashi took part in the 2012 World Tag League, teaming with Captain New Japan under the team name "Captain Ace". The team lost all six of their matches with Captain New Japan being pinned in each match. On January 4, 2013, at Wrestle Kingdom 7 in Tokyo Dome, Tanahashi made his sixth successful defense of the IWGP Heavyweight Championship against the previous year's G1 Climax winner, Kazuchika Okada. At the following pay-per-view, The New Beginning on February 10, Tanahashi made another successful title defense against Karl Anderson, avenging his loss from the 2012 G1 Climax. On March 3 at New Japan's 41st anniversary event, Tanahashi defeated IWGP Junior Heavyweight Champion Prince Devitt in a special non-title main event. On April 7 at Invasion Attack, Tanahashi lost the IWGP Heavyweight Championship back to Kazuchika Okada. On June 22 at Dominion 6.22, Tanahashi attempted to earn another shot at the title, but was defeated in a number one contender's match by Prince Devitt, following interference from Devitt's new Bullet Club stable. On July 5, Tanahashi teamed with Jushin Thunder Liger to defeat Bullet Club member Tama Tonga and El Terrible for the CMLL World Tag Team Championship. From August 1 to 11, Tanahashi took part in the 2013 G1 Climax, where he opened by losing three of his first four matches. However, Tanahashi bounced back to wrestle IWGP Heavyweight Champion Kazuchika Okada to a time limit draw and winning his other four matches to win his block and advance to the finals of the tournament. In the finals on August 11, Tanahashi was defeated by Tetsuya Naito. After returning from a tour of CMLL, Tanahashi and Liger lost the CMLL World Tag Team Championship on September 14 to Bullet Club members Rey Bucanero and Tama Tonga, following outside interference from the rest of the group. Tanahashi's rivalry with Bullet Club leader Prince Devitt built to a Lumberjack Deathmatch on September 29 at Destruction, where Tanahashi was victorious. With the Devitt rivalry behind him, Tanahashi once again set his sights on the IWGP Heavyweight Championship, challenging Kazuchika Okada at the end of the event. Tanahashi failed in his title challenge on October 14 at King of Pro-Wrestling. In a post-match interview, Tanahashi bid farewell to the IWGP Heavyweight Championship as he had proclaimed that he would not challenge for the title again, should he lose to Okada. Tanahashi then entered the IWGP Intercontinental Championship picture, after being nominated as the next challenger by champion Shinsuke Nakamura, setting up the first title match between the two longtime rivals in over two years. In November, Captain Ace reunited for the 2013 World Tag League. Much like the previous year, the team lost their first five matches, but on the final day they finally picked up a win over Bad Luck Fale and Prince Devitt, costing the Bullet Club team a spot in the semifinals.