Before becoming an executive, the late Satoru Iwata worked as a programmer for HAL Laboratory and Nintendo, writing code for classic titles like Super Smash Bros. and Pokémon Gold and Silver.
Frank Cifaldi, a gaming historian who leads restoration at indie developer Backbone Entertainment, recently dug up prototypes of some of the first games that Iwata worked on at Nintendo. He found and purchased some "fishy" Famicom boards for Hyper Olympic, Stargate, Soccer, and Joust. These boards are essentially small discs that contain prototype versions of these games, used by Nintendo developers to test the game's engine.
Joust, the oldest of these titles, was the first game that Iwata worked on after being hired by Nintendo. The code for the game was single-handedly written by Iwata, and the game was supposed to launch in 1983, as part of a partnership between Nintendo and Atari. The partnership was cancelled before the game ever came to light, and Joust was instead released by HAL, Iwata's old employer, in 1987. This board for Joust was the first piece of code that Iwata ever wrote for Nintendo, and according to Cifaldi, might be the only known prototype of an unreleased first-party Nintendo game in existence.
There are a few images of the Famicom boards purchased by Frank Cifaldi in the gallery below. Cifaldi did state that there's a small chance that these boards have been forged by the man he bought them from, but he does not believe this is the case. Regardless, the code inside of the boards could not possibly have been forged, so even if the boards aren't authentic, they still contain Iwata's earliest work on these games.