Super Mario Bros. is one of the most renowned, acclaimed and influential video games of all time — and no-one knows for sure when it was released in the US. That's the unbelievable takeaway from a Gamasutra feature in which Frank Cifaldi attempted to prove once and for all exactly when the game went on sale (though there's little dispute over the original Japanese release of September 13th, 1985). Cifaldi notes a consensus that the game came to US shores at some point in 1986, but Nintendo itself lists the game as launching on October 18, 1985.
Problem is, it turns out there's no way to verify either claim — retailers from the time all seem to offer conflicting recollections, with copyright filings and "anonymous but reliable" tipsters adding further confusion to the mix. At best, it seems all we can say is that the game was released in October or November 1985 during the NES's initial market test release in New York City. It's almost impossible to envisage even the most mediocre of modern video games having its release date lost to the annals of time in such a fashion, but this only adds to the mystique surrounding Super Mario Bros. While worrying about digital preservation is one thing, it's quite another when we can't even rely on our history books.