The International Wrestling Grand Prix (IWGP) Heavyweight Championship is the top professional wrestling title in Japanese promotion New Japan Pro Wrestling (NJPW). It was created in 1987 with NJPW founder Antonio Inoki defeating Masa Saito in the finals of the annual IWGP tournament.
Throughout the history of the championship, several wrestlers have been forced to relinquish the title due to an inability to participate in title defenses. When a wrestler has been injured or unable to compete for other reasons, tournaments have been held to determine the new champion.
In 2006, then-champion Brock Lesnar was stripped of the title for being unable to defend it; however, Lesnar claims he was owed money by NJPW and kept the physical belt. He signed with Antonio Inoki's Inoki Genome Federation (IGF) in 2007, losing the championship to Kurt Angle on the inaugural broadcast. Angle later lost the belt in a unification match to the NJPW-recognized champion Shinsuke Nakamura in 2008.
Title reigns are determined either by professional wrestling matches featuring wrestlers involved in pre-existing scripted feuds, plots and storylines or by other scripted circumstances, where wrestlers were awarded the title. Wrestlers are portrayed as either villains or fan favorites as they followed a series of tension-building events, which culminated in a wrestling match or series of matches for the championship.
The inaugural champion was Antonio Inoki, who beat Masa Saito on June 12, 1987. Hiroshi Tanahashi holds the record for most reigns with seven. Shinya Hashimoto's 489 days is the longest reign in the title's history. Shinsuke Nakamura is the youngest champion at 23 years and 288 days, while Genichiro Tenryu is the oldest champion at 49 years and 311 days. Overall, there have been a total of 26 recognized champions, who have had a combined 62 official reigns.
- New Japan Pro Wrestling
- Champion history - History of the wrestlers who have held the belt.
- Title matches - Matches in which the title was defended.
- Champion gallery - A gallery of all champions.