Answer
The Grand Slam is a prestigious title in New Japan Pro-Wrestling (NJPW) that is awarded to a wrestler who has won the IWGP Heavyweight Championship, the IWGP Intercontinental Championship, the IWGP United States Championship, and the NEVER Openweight Championship. The first wrestler to accomplish this feat was Hiroshi Tanahashi, who won all four titles between 2008 and 2013.