The origin of this game and its attribution to Einstein and Oppenheimer is greatly disputed. And yet it has been floating online for more than two decades now without a proper source.
> Some (Dennis Holding and Andy Soltis) have attributed the above game to Albert Einstein's son, Hans Albert (1904-1969), and played at Berkeley in 1945 where Hans taught. But Hans Albert did not play chess. There is no indication that J. Robert Oppenheimer was in Berkeley in 1945. He was either at Los Alamos, New Mexico or Princeton, New Jersey in 1945. He was at Berkeley from 1929 to 1933.
> Andy Soltis, writing in the July, 1979 issue of Chess Life on page 372 in an article called "Science at Play" says this game was apparently played in the late 1940s when Hans Albert Einstein, son of Albert Einstein, and Robert Oppenheimer were both on the faculty at the University of California at Berkeley.
> Another source says that Black was not Robert Oppenheimer the physicist, but Max Oppenheimer (1885-1954), the European artist.
https://www.chess.com/blog/ThummimS/albert-einstein-vs-j-rob...
It sounds like the lack of first names in the record might have caused some confusion
That book used the conditional tense, to convey uncertainty about the game’s authenticity (‘la partie suivante qui aurait été gagnée par Einstein contre le grand physicien Robert Oppenheimer’)
source: https://www.chesshistory.com/winter/winter04.html item: 3533
The conditional tense here in French is used to report that something has been asserted by someone, without taking a position one way or the other on whether the assertion is true. I don't think there is an exact grammatical equivalent in English.