As a U.S. Navy lieutenant overseeing logistical movement of arms at Guadalcanal Air Base in the Solomon Islands and other posts during World War II, Richard Nixon’s unit was subjected to such regular Japanese air bombings, it became known as “Murder, Incorporated.”

But once the future president was transferred to the more peaceful Green Island, he found time for more leisurely pursuits—namely poker. In fact, he became such a card shark that, when he returned from his service, he brought home thousands of dollars in winnings—enough cash to help fund his first run for political office, when he won a California congressional seat in 1946.

“He was the finest poker player I have ever played against,” former Navy comrade James Udall recalled in a 1970 Life magazine interview. “I once saw him bluff a lieutenant commander out of $1,500 with a pair of deuces.”

“I never saw him lose,” another Navy man, Lester Wroble, told Life.

Nixon, who left his job as a lawyer at a federal agency in Washington at age 29 to join the Navy, was an unlikely card shark. He grew up in a deeply religious Quaker family in southern California, where gambling—along with drinking and swearing—was frowned upon. (His Quaker background would have also excused him from military service in the war, had he chosen not to enlist.)

When he arrived at an air base in Green Island in the Solomons in 1944 to supervise the loading and unloading of cargo aircraft, by one account, he didn’t even know how to play cards.

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But as detailed in Jonathan Aitken’s biography, Nixon: A Life, the future president apparently was intrigued after he spent a couple of evenings watching his fellow officers playing the game. (The officers usually played five-card stud or draw, with nothing wild, according to the Life article.)

In Aitken’s account, Nixon reportedly asked a poker-playing friend, James Stewart, if there was a sure way to win the game. Stewart replied that if there was, “I’d be sitting in Brazil with five million bucks in the bank.”

Nevertheless, Stewart shared with Nixon a strategy that he thought might work for a highly disciplined player. It involved turning in the cards about 80 percent of the time, and staying in the game only when you felt confident that you held the best hands. It was a boring way to gamble, but Nixon apparently wasn’t looking to be entertained. He wanted to make some cash.

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“In everything he did, Nixon tried to master the fundamentals,” Ken Hughes, a historian with the University of Virginia’s Miller Center, and author of the 2015 book Fatal Politics: The Nixon Tapes, the Vietnam War, and the Casualties of Reelection, says in an email_._ “When he wanted to learn poker in the Navy, he studied the game before risking any of his money, spending hours and days with the best players he could find, listening to their lectures, learning their moves, playing practice games with no stakes.

Hughes explains that poker wasn’t just a game to Nixon, it was a skill to be honed and then put to use turning a profit. “It was work, and Nixon always worked hard, well and successfully,” Hughes says.

“I think Nixon’s approach to poker shows first of all the enormous self-discipline and determination to succeed in his character,” Aitken says via email. “He probably did not get much pleasure from the game, but I feel he would have obtained great satisfaction for it because he achieved his goal, which was to build up money for his savings.”

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Nixon quickly mastered poker strategy, he also apparently became adept at reading the other players and figuring out how to exploit their psychological flaws. “I found poker instructive as well as entertaining and profitable,” Nixon later wrote in RN: The Memoirs of Richard Nixon. “I learned that the people who have the cards are usually the ones who talk the least and the softest; those who are bluffing tend to talk loudly and give themselves away.”

The poker-playing moment that stuck in Nixon’s mind was the evening when he drew a royal flush in diamonds. “The odds against this are about 650,000 to one, and I was naturally excited,” Nixon recalled. “But I played it with a true poker face, and won a substantial pot.”

By Nixon’s own account, on one occasion he passed up an opportunity to have dinner with legendary aviator Charles Lindbergh, who was visiting the base, because it conflicted with a poker game that he had agreed to host. On Green Island, “Our poker games were more than idle pastimes, and the etiquette surrounding them was taken very seriously,” he explained.

In July 1944, Nixon’s overseas tour ended when he was ordered to return stateside to finish his Navy stint. “When the war ended, so did Nixon’s poker-playing career,” Hughes says.

When he came home to his wife Pat, Nixon brought a sizeable stack of cash. It’s not completely clear how much money Nixon won at poker during his Navy days, but according to Nixon biographer John A. Farrell’s book Richard Nixon: The Life, he told his family that he pocketed about $8,000—slightly more than $111,000 in today’s dollars. Aitken cites a lower estimate of $6,800.

Nixon originally planned to pool that money with his wife’s salary to buy a house. But instead, after receiving a letter from businessman Herman Perry urging him to run for a congressional seat in California’s 12th District, he decided to take on Democratic incumbent Jerry Voorhis.

“Pat was dubious about spending our savings on what was at best a risky political campaign,” Nixon recalled in his memoir. “But the more we thought about the possibility of returning to Washington as a congressional family, the more enthusiastic we became.”

Nixon’s poker money made up a portion of the war chest that he amassed in his run against Voorhis, whom he defeated easily in the fall of 1946.

“Nixon's first campaign certainly cost more than he’d saved from his poker winnings, but having some money saved meant that Nixon could afford to take a calculated risk on running for office,” Hughes says.

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“He would have been contributing 20 percent of the entire campaign costs from his accumulated poker winnings,” Aitken says. “Very few candidates then or now contribute 20 percent of a Congressional campaign costs personally.”

Though Nixon apparently didn’t play poker as president, during Watergate he did sometimes resort to poker metaphors, according to former White House counsel John Dean’s book, The Nixon Defense: What He Knew and When He Knew it.

On one occasion, for example, Nixon derided his FBI director, L. Patrick Gray, for showing too much outward bravado in a congressional hearing, which he felt betrayed an inner lack of confidence. As Nixon said, “With a good poker player, you never know either way, if he’s got the cards or if he doesn’t.”