What is documented. Joseph Hobson Jagger (1830–1892), a Yorkshire textile businessman facing bankruptcy, travelled to Monte Carlo around 1880–81 with his son and nephew on borrowed money. He studied the casino's roulette tables for about a month to see which numbers came up most often, then bet on them. He is reputed to have won over 2 million francs over several days, about £80,000 at the time, put at £7.5 million in 2018 money by The Times. The manufacturers later introduced movable partitions into the tables to defeat his method. Popular retellings date the exploit to 1873; the 2018 biography by Anne Fletcher, on which the current record rests, places the trip around 1880–81.

Why it worked: a biased wheel is not a hot streak

Jagger did not believe numbers were "due" or "hot". He assumed the opposite: that a Victorian wheel, hand-made from wood and metal, might be physically uneven, so that some pockets caught the ball slightly more often than $1/37$. A month of recorded spins is enough to show that. If a pocket's true frequency is, say, $1/30$ instead of $1/37$, a straight-up bet paying 35 to 1 has expected value $35 \cdot \tfrac{1}{30} - \tfrac{29}{30} = +\tfrac{6}{30} = +20\%$ per unit, and the house edge is gone.

That is the only sense in which a "hot number" has ever been real: as a symptom of a defective wheel, measurable over thousands of spins, persisting until the wheel is repaired or moved. A number that is hot over the last 50 spins on a sound wheel is noise; the chance of any given number appearing at least 4 times in 50 spins on a fair wheel is about $1 - \sum_{{j=0}}^{{3}} \binom{{50}}{{j}} (1/37)^j (36/37)^{{50-j}} \approx 4.6\%$, so with 37 numbers on the board, one or two "hot" numbers appear by chance almost every time.

Why it cannot happen today

  • Wheels are precision-made and tested. Modern wheels use machined components with far smaller tolerances than 1880s woodwork, and casinos track every spin electronically to detect a bias long before a player could.
  • Wheels are rotated and maintained. The movable partitions introduced after Jagger were the first countermeasure; today wheels are moved between tables and serviced on schedule, which erases any bias a player has measured.
  • Online roulette has no wheel. A certified random number generator has no pockets to wear. Under the UK Gambling Commission's Remote Technical Standards it must be "acceptably random", verified by an approved third-party test house, and games that adapt to past results are prohibited.

The two famous Monte Carlo stories are opposites. Jagger (c. 1880) won because a wheel was not random. The players of 18 August 1913 lost because they assumed a wheel that was random owed them a red after 26 blacks. Hot-number boards in casino lobbies invite the second mistake while pretending to be the first.

What is legend

Several details repeated online are not supported by the biographical record: the exact year 1873, the hiring of six clerks, the specific nine biased numbers, and the link to the 1892 music-hall song "The Man Who Broke the Bank at Monte Carlo". The song is thought to be about Charles Wells, not Jagger. Brewer's Dictionary says Jagger died "probably mainly from boredom"; his death certificate gives diabetes. Treat the numbers above as reputed, and the mechanism as the point.

Sources

  1. Wikipedia. "Joseph Jagger", citing Fletcher, A. (2018), From the Mill to Monte Carlo, Amberley; Halifax Courier, 5 April 2007; Bird, S., The Times, 23 March 2004; Brewer's Dictionary of Phrase and Fable, 16th ed., 1999, p. 739. en.wikipedia.org/wiki/Joseph_Jagger (accessed 24 October 2026).
  2. UK Gambling Commission. Remote Gambling and Software Technical Standards, RTS 7A. gamblingcommission.gov.uk
  3. Wikipedia. "Gambler's fallacy", Monte Carlo Casino, 18 August 1913. en.wikipedia.org/wiki/Gambler%27s_fallacy

Frequently asked questions

Who was Joseph Jagger?

Joseph Hobson Jagger (1830–1892) was a textile businessman from Shelf, Yorkshire. Facing bankruptcy, he went to Monte Carlo around 1880–81 and won a reputed 2 million francs, about £80,000 then, by betting on numbers a wheel favoured because of a physical defect. The casino's suppliers then introduced movable partitions to stop the method.

Did Joseph Jagger use hot numbers?

Only in the physical sense. He recorded a month of spins to find a wheel whose pockets were uneven, so some numbers really did come up more often than 1 in 37. On a sound wheel, and on any online wheel, there is no such defect, and recent frequency carries no information about the next spin.

Can you find a biased roulette wheel today?

In practice no. Modern wheels are precision-manufactured, electronically monitored for bias, rotated between tables and serviced on schedule. Online roulette uses a certified random number generator with no physical pockets. The Jagger method depended on 1880s manufacturing and on a casino that did not track its own wheels.

Was Jagger the man who broke the bank at Monte Carlo?

He did break the bank in the casino's sense, which meant winning more than a table's 100,000-franc daily reserve. But the 1892 song of that name is thought to be about Charles Wells, not Jagger, despite Brewer's Dictionary linking the two.