Which heavyweight boxer holds the record for the most knockouts in title fights?

Joseph Louis Barrow (May 13, 1914 – April 12, 1981), best known as Joe Louis and nicknamed the "Brown Bomber", was an American professional boxer who competed from 1934 to 1951. He reigned as the world heavyweight champion from 1937 to 1949, and is considered to be one of the greatest heavyweights of all time. Louis' championship reign lasted 140 consecutive months, during which he participated in 26 championship fights. The 27th fight, against Ezzard Charles in 1950, was a challenge for Charles' heavyweight title and so is not included in Louis' reign. Louis was victorious in 26 title defenses, a world record second only to Julio César Chávez with 27. In 2005, Louis was ranked as the best heavyweight of all time by the International Boxing Research Organization, and was ranked number one on The Ring magazine's list of the "100 greatest punchers of all time".

In total, Louis made 25 defenses of his heavyweight title from 1937 to 1948, and was a world champion for 11 years and 10 months. Both are still records in the heavyweight division, the former in any division. His most remarkable record is that he knocked out 23 opponents in 27 title fights, including five world champions.