von Neuman scored 4.5/9 in the Open Section, including a draw with a GM and a win over a 2350 rated player. It was the bulge in one of his pockets which appeared to make a soft humming or buzzing sound at important points in the game that aroused suspicions.
Von Neumann won the unrated prize of $800 but before organizers handed over the check he was quizzed by the tournament director and was unable to demonstrate even a rudimentary knowledge of some simple chess concepts. When asked to solve a simple puzzle he refused, turned and left, and has never been seen again at a tournament.
von Neumann drew with GM Helgi Olafsson in the second round. But in round four he suddenly stopped playing at move nine and lost on time against Danny Shapiro who went on to gain the IM title. Here’s that game:
This is how his game from round nine went: