It gave me insight into Buffett that I never had from the biographies and endless features, profiles and news reports that we Buffett junkies have read.
Buffett said he didn't get really serious about bridge until two things came along: Osberg and computers.
He met Osberg at a bridge tournament in New York back in the early 1990s.
"I love the game, and I love my partner," Buffett said of Osberg. "She's a fabulous teacher, extremely smart and very patient."
Computers are a different story for Buffett, who historically stayed away from investing in technology. That has changed recently, with big bets in IBM and Apple.
"Before computers, I would have to get three, usually guys, and get them together in one place on a Saturday," he said. "There was a lot of physical arranging. With a computer, you can be playing in 15 seconds."
Now, he said, "I play a lot. . . at least four sessions a week, about two hours a session."
Buffett was reluctant to buy a computer at first, even after he was urged on by his close friend, Microsoft co-founder Bill Gates.
"Bill said, 'You've got to get a computer to do your income tax,' " Buffett recalled. "I said, 'I don't have income. Berkshire doesn't pay a dividend.' He said, 'You can keep track of stocks.' 'I only have one stock,' " Buffett said he told Gates.
Osberg eventually persuaded Buffett to get a computer so he could play bridge.
"I was traveling on business in the Midwest, and he stopped his jet on his way to Omaha and picked me up," Osberg said. It was her first time on a private jet. Osberg helped Buffett buy the desktop computer in 1994 through the Nebraska Furniture Mart, one of Buffett's many companies. "It was waiting for us when we got to his home," she said.
I asked Buffett what he likes about bridge.
The Oracle said he enjoys the game for the intellectual stimulation. It's neither relaxing nor tension-filled. Just good mind exercise.
"It really is a game that you are never going to see the same hand twice," Buffett said. "You can play a hand every six or seven minutes every day for the rest of your life, and you will never see the same hand. It's a game you can enjoy when you are in your 90s, and you are seeing a different intellectual challenge every seven minutes. It's the best exercise there is for the brain."
Buffett said he enjoys and is challenged by the various systems - or strategies - bridge partners use to communicate with each other.
"Every single action taken by your partner or your opponents, you have to keep drawing inferences from," he said. "They keep getting modified. It's a fascinating game. You are learning from every word spoken and not spoken."
I asked Buffett whether he plays often with his alter ego, Charlie Munger. The blunt-spoken, curmudgeonly Munger is Buffett's longtime friend and business partner.
At 93, Munger is vice chairman of Berkshire Hathaway, the cornerstone of his and Buffett's fortunes.
"I have played with him in Los Angeles," Buffett said. "Charlie had a regular bridge game for 40 years."
Buffett said Munger may not be a student of the various bridge systems, but Munger succeeds because "he's just so damn smart." (Munger and Buffett are known for smart contrarian investing approaches that emphasize the avoidance of mistakes rather than making brilliant moves.)
Gates, on the other hand, is a Harvard dropout who made one brilliant move: co-founding Microsoft, the powerhouse software company that has created an enormous amount of wealth for millions (including the Bill & Melinda Gates Foundation) over the past 42 years.
Gates loves bridge and is a regular tournament partner of Osberg's.
"Bill doesn't get a chance to play a lot," Buffett said. "I spend way more time playing than Bill. He loves playing bridge. He likes to play in tournaments. But he has a way busier schedule than me."
Osberg recalled Buffett's first bridge tournament, in Albuquerque. They made it to the finals after two grueling preliminary rounds - a "miraculous" achievement, Osberg said.
But Buffet had had enough.
"He said, 'I can't do it anymore.' It was so stressful, he didn't want to play in the finals," Osberg said.
"I had no business being in it at all," Buffett said. "We were playing people not as good as Sharon was but a whole lot better than I was. I dropped out. I was on the board of USAir at the time, so I said I had to get back to a board meeting. This was not great behavior on my part. I love the game, but playing in tournaments is too many hours of concentration."
Osberg said Gates and Buffett have different approaches to bridge.
"Bill is very scientific. He reads and studies on his own," Osberg said. "Warren enjoys playing. Warren has good instincts."
Buffett said Gates has a leg up because of his reading speed: "Bill reads very fast, so he would cover a lot more ground."
Buffett recalled a 1995 trip to China organized by Gates and his wife, Melinda. About seven couples participated. Gates showed up with a handful of bridge books. The obsessed billionaires proceeded to play throughout the journey.
"We were playing bridge while everyone was looking at the scenery," Buffett said. "We played on the bus while balancing cards on our knees."
Buffett said he eventually received a scenic photo of the trip from Gates. The Microsoft co-founder had scrawled a note across the bottom: "A great place for a bridge game."
Bridge is embedded in their friendship. It even came up during a discussion on artificial intelligence during their first meeting in the mid-1990s.
"This was a hot subject at the time, with all those things on chess, IBM, Deep Blue," Buffett said. "When I met Bill on July 5, 1991, I said to him, 'Will a computer be built that can beat the best bridge players?' Bill said a computer will win at chess eventually. But it won't win at bridge."
IBM's Watson may have something to say about that.