Four Horsemen of Aberdeen

The Four Horsemen of Aberdeen is the name used to describe a group of blackjack players who are credited with being the first to develop an accurate strategy for winning at the game of blackjack. The four men, Wilbert Cantey, Roger Baldwin, James McDermott and Herbert Maisel, were later inducted into the Blackjack Hall of Fame in 2008 in recognition of their achievement.

Using nothing but the rudimentary “adding machines” that were available on their Army base, the four men spent all of their free time during the 1950s working on ways to mathematically beat the blackjack system.

The group first became interested in the idea after a night of poker, during which one player chose blackjack as his dealer’s choice game. After discussing the rules, Baldwin was surprised to learn that the blackjack dealer had to stand on 17 and hit on 16 at Las Vegas casinos. Wondering why this rule would be put into place, Baldwin began working out some basic formulas and later asked his sergeant if you could use the base’s calculators to help him with his number crunching. Soon, the other three “Horsemen” joined him in his pursuit to find the answers to these mathematical questions.

The fact that Baldwin and his Army buddies were so interested in developing these mathematical formulas doesn’t come as too much of a surprise when considering the background of the group. Though merely a private in the Army, Baldwin held a master’s degree from Columbia University in mathematics at the time. McDermot also held a master’s degree from Columbia and Maisel went on to become a professor at Georgetown. Cantey also held a master’s degree and had a strong interested in gambling. In fact, he was “encouraged” to leave the seminary because of his passion for hustling with cards and pool. He later went on to become a researchers for the government.

The group of men spent a year and a half crunching numbers and developing their basic blackjack strategy. Their findings were published in the Journal of the American Statistical Association in 1956 and then again in the 1957 book Playing Blackjack to Win. The book didn’t remain in print for long, however, and sold for only $1.75. In all, McDermott received only $23 in royalties from the book, which contained strategies and maneuvers that were considered to be shocking at the time. When Edward Thorp ran their numbers through MIT computers years later, however, he found their research to be accurate to within just a couple hundredths of a percentage point. Quite impressive for four guys with nothing but a desk calculator to aid them in their calculations.