Roulette wheels, numbered 0 to 36, have 37 slots, theoretically offering a one in 37 chance of success. However, García-Pelayo speculated that certain numbers might appear more often than others.
He discovered imperfections in the wheels, causing some numbers to win as frequently as every 28 spins instead of 36.
Utilizing advanced computer modeling, García-Pelayo determined which numbers were more probable and eventually won a substantial 600,000 euros ($624,850) in a single day, exceeding a million euros in total.
Nonetheless, the casino decided to pursue legal action against him.
By 1994, the casino discovered García-Pelayo’s strategy and banned him and his associates from entering.
The case went to court, resulting in a decade-long legal battle, and ultimately a judge ruled that García-Pelayo had not engaged in cheating, obligating the casino to welcome him back.
However, he chose not to return, citing that he was ‘too well known’ after the incident.
García-Pelayo’s case isn’t unique; others have exploited similar flaws in the system.
Joseph Jagger, a mechanic, noticed a wheel bias favoring numbers 7, 8, 9, 17, 18, 19, 22, 28, and 29 while working at a casino.
Spreading his bets over a few days, Jagger won an impressive two million francs, as reported by Bettors Insider.
Richard Jarecki also identified a bias in a European roulette wheel, leading him to place strategic bets and win significant amounts over several years. He switched casinos to avoid detection, accumulating over $1 million.
Similarly to García-Pelayo, some casinos eventually banned him from returning.
Ashley Revell opted for a different strategy, relying entirely on chance. He sold all his possessions and wagered his life savings on a single roulette spin, which is certainly one way to gamble.