Question: Who is the golfer having won the most masters green jackets?

full_context: Document 1: Jack Nicklaus: Jack William Nicklaus (born January 21, 1940), nicknamed The Golden Bear, is an American retired professional golfer. In the opinion of many observers, he is the greatest golfer of all time. During a span of more than 25 years, he won a record 18 major championships, three ahead of Tiger Woods (15). Nicklaus focused on the major championships—Masters Tournament, U.S. Open, Open Championship and PGA Championship—and played a selective schedule of regular PGA Tour events. He has competed in more major championships (164) than any other player. He finished with 73 PGA Tour victories, third on the all-time list behind Sam Snead (82) and Tiger Woods (81).
Document 2: List of men's major championships winning golfers: Jack Nicklaus has won the most majors; he won 18 during his career. Second on the list is Tiger Woods, who has won 14 majors to date; his most recent major victory was at the 2008 U.S. Open. Walter Hagen is third with 11 majors; he and Nicklaus have both won the most PGA Championships with five. Nicklaus also holds the record for the most victories in the Masters, winning the competition six times. Nicklaus also shares the record for the most U.S. Open victories with Willie Anderson, Bobby Jones and Ben Hogan, each winning this competition four times. Harry Vardon holds the record for the most Open Championship victories, winning six times during his career. Nicklaus, Woods, Hogan, Gary Player and Gene Sarazen are the only golfers to have won all four of the majors during their career, thus achieving the so - called career slam.
Document 3: List of Masters Tournament champions: Jack Nicklaus holds the record for the most Masters victories, winning the tournament six times during his career. Nicklaus is also the oldest winner of the Masters: he was 46 years 82 days old when he won in 1986. Nicklaus, Nick Faldo, and Tiger Woods co-hold the record for most consecutive victories with two. Woods was the youngest winner of the Masters, 21 years 104 days old when he won in 1997. Woods also set the record for the widest winning margin (12 strokes), and the lowest winning score, with 270, 18 below par (- 18) in 1997. The latter was equaled by Jordan Spieth in 2015.
Document 4: List of The Open Championship champions: Harry Vardon holds the record for the most Open Championship victories, winning six times during his career. The oldest winner of the Open Championship is Tom Morris Sr. (or Old Tom Morris) who was 46 years and 102 days old when he won in 1867. His son, Tom Morris Jr., is the youngest winner of the championship, he was 17 years and 156 days old when he won the 1868 Open Championship. He also won the most consecutive times with four victories (1868 -- 72). Henrik Stenson holds the dual distinction of being both the most strokes under par for 72 holes (− 20) and also recording the lowest total score (264) when he won in 2016.
Document 5: List of men's major championships winning golfers: Jack Nicklaus has won the most majors, achieving 18 victories during his career. Second on the list is Tiger Woods, who has won 14 majors to date; his most recent major victory was at the 2008 U.S. Open. Walter Hagen is third with 11 majors; he and Nicklaus have both won the most PGA Championships with five. Nicklaus also holds the record for the most victories in the Masters, winning the tournament six times. Additionally, Nicklaus shares the record for the most U.S. Open victories with Willie Anderson, Bobby Jones and Ben Hogan, each winning four times. Harry Vardon holds the record for the most Open Championship victories, winning six times during his career. Nicklaus, Woods, Hogan, Gary Player and Gene Sarazen are the only golfers to have won all four of the majors during their career, thus achieving the so - called career slam.
Document 6: Tiger Woods: Tiger Woods Woods in June 2018 Full name Eldrick Tont Woods Nickname Tiger (1975 - 12 - 30) December 30, 1975 (age 42) Cypress, California Height 6 ft 1 in (185 cm) Weight 185 lb (84 kg) Nationality United States Residence Jupiter Island, Florida Spouse Elin Nordegren (2004 -- 2010) Children Career College Stanford University (did not graduate) Turned professional Current tour (s) PGA Tour (joined 1996) Professional wins 107 Number of wins by tour PGA Tour 80 (2nd all time) European Tour 40 (3rd all time) Japan Golf Tour Asian Tour PGA Tour of Australasia Other 16 Best results in major championships (wins: 14) Masters Tournament Won: 1997, 2001, 2002, 2005 U.S. Open Won: 2000, 2002, 2008 The Open Championship Won: 2000, 2005, 2006 PGA Championship Won: 1999, 2000, 2006, 2007 Achievements and awards PGA Tour Rookie of the Year PGA Player of the Year 1997, 1999, 2000, 2001, 2002, 2003, 2005, 2006, 2007, 2009, 2013 PGA Tour Player of the Year 1997, 1999, 2000, 2001, 2002, 2003, 2005, 2006, 2007, 2009, 2013 PGA Tour leading money winner 1997, 1999, 2000, 2001, 2002, 2005, 2006, 2007, 2009, 2013 Vardon Trophy 1999, 2000, 2001, 2002, 2003, 2005, 2007, 2009, 2013 Byron Nelson Award 1999, 2000, 2001, 2002, 2003, 2005, 2006, 2007, 2009 FedEx Cup Champion 2007, 2009 (For a full list of awards, see here)
Document 7: 1971 PGA Championship: Jack Nicklaus won the second of his five PGA Championships, two strokes ahead of Billy Casper, the reigning Masters champion. Nicklaus led wire-to-wire, and held a four-stroke lead over Gary Player after 54 holes, with Casper seven shots back. The two were pre-tournament favorites, along with Arnold Palmer, who shot an opening round 75 and finished at 289 (+1), eight strokes back.
Document 8: Walter Hagen: Walter Charles Hagen (December 21, 1892 – October 6, 1969) was an American professional golfer and a major figure in golf in the first half of the 20th century. His tally of 11 professional majors is third behind Jack Nicklaus (18) and Tiger Woods (15). Hagen is widely considered one of the greatest golfers ever.
Document 9: List of golfers with most PGA Tour wins: The column for Major refers to so - called ``Professional Majors ''. The U.S. Amateur and the British Amateur were also considered to be majors for much of their history, but these championships are not considered here. Players under 50 years of age are shown in bold. During the last 30 years, only three players have won PGA Tour events after their 50th birthday. A golfer becomes eligible to compete on PGA Tour Champions, against other older players, at that age. Craig Stadler won in 2003 at age 50, Fred Funk won in 2007 at age 50, and Davis Love III won in 2015 at age 51. Sam Snead is the oldest to win a PGA event, at age 52, in 1965. Others who have won PGA Tour events past age 50 include Jim Barnes, John Barnum, and Art Wall, Jr. The rarity of golfers winning a non-senior event at that age is not restricted to the PGA Tour; Miguel Ángel Jiménez is the only golfer to win a European Tour event after turning 50, doing so in 2014.
Document 10: Tiger Woods: Tiger Woods Woods in June 2014 Full name Eldrick Tont Woods Nickname Tiger (1975 - 12 - 30) December 30, 1975 (age 42) Cypress, California Height 6 ft 1 in (185 cm) Weight 185 lb (84 kg) Nationality United States Residence Jupiter Island, Florida Spouse Elin Nordegren (2004 -- 2010) Children Career College Stanford University (did not graduate) Turned professional Current tour (s) PGA Tour (joined 1996) Professional wins 106 Number of wins by tour PGA Tour 79 (2nd all time) European Tour 40 (3rd all time) Japan Golf Tour Asian Tour PGA Tour of Australasia Other 16 Best results in major championships (wins: 14) Masters Tournament Won: 1997, 2001, 2002, 2005 U.S. Open Won: 2000, 2002, 2008 The Open Championship Won: 2000, 2005, 2006 PGA Championship Won: 1999, 2000, 2006, 2007 Achievements and awards PGA Tour Rookie of the Year PGA Player of the Year 1997, 1999, 2000, 2001, 2002, 2003, 2005, 2006, 2007, 2009, 2013 PGA Tour Player of the Year 1997, 1999, 2000, 2001, 2002, 2003, 2005, 2006, 2007, 2009, 2013 PGA Tour leading money winner 1997, 1999, 2000, 2001, 2002, 2005, 2006, 2007, 2009, 2013 Vardon Trophy 1999, 2000, 2001, 2002, 2003, 2005, 2007, 2009, 2013 Byron Nelson Award 1999, 2000, 2001, 2002, 2003, 2005, 2006, 2007, 2009 FedEx Cup Champion 2007, 2009 (For a full list of awards, see here)
Document 11: 1965 Masters Tournament: Jack Nicklaus, age 25, won the second of his six Masters titles with a score of 271 (−17), at the time a tournament record, three strokes better than Ben Hogan's 274 in 1953. It was equaled in 1976 by Raymond Floyd and surpassed in 1997 by Tiger Woods' 270 (−18). Nicklaus' winning margin of nine strokes also stood until 1997, when Woods was victorious by twelve strokes to win his first green jacket. It was the fourth of a record 18 major titles won by Nicklaus in his career.
Document 12: Men's major golf championships: Along with his record 18 major victories, Jack Nicklaus also holds the record for most runner - up finishes in major championships, with 19, including a record 7 at the Open Championship. Phil Mickelson has the second most with 11 runner - up finishes after the 2016 Open Championship, which includes a record 6 runner - up finishes at the U.S. Open, the one major he has never won. Arnold Palmer had 10 second places, including three in the major he never won, the PGA Championship. There have been three golfers with 8 runner - up finishes -- Sam Snead, Greg Norman and Tom Watson. Norman shares the distinction of having lost playoffs in each of the four majors with Craig Wood (who lost the 1934 PGA final -- at match play -- on the second extra hole).
Document 13: List of golfers with most PGA Tour wins: This is a list of golfers who have won five or more official (or later deemed as historically significant) money events on the PGA Tour. It is led by Sam Snead with 82 wins, Tiger Woods with 80, and Jack Nicklaus with 73.
Document 14: 1997 Masters Tournament: Tiger Woods won his first major championship, twelve strokes ahead of runner-up Tom Kite. Through 2019, the margin of victory and four-day score of 270 (−18) are tournament records. Woods also became both the youngest (21) and the first non-white player to win at
Document 15: Masters Tournament: The first winner of the Masters Tournament was Horton Smith in 1934, and he repeated in 1936. The player with the most Masters victories is Jack Nicklaus, who won six times between 1963 and 1986. Arnold Palmer and Tiger Woods have each won four, and Jimmy Demaret, Gary Player, Sam Snead, Nick Faldo, and Phil Mickelson have three titles to their name. Player was the tournament's first overseas winner with his first victory in 1961. Two - time champions include Byron Nelson, Ben Hogan, Tom Watson, Seve Ballesteros, Bernhard Langer, Ben Crenshaw, José María Olazábal, and Bubba Watson.
ground_truth: an American retired professional golfer
sub_queries: who has won the most masters green jackets Answer: Jack Nicklaus
Who is Jack Nicklaus ? Answer: an American retired professional golfer