Weekly chess column
Gregory Kaidanov seriously upset the standings in the 2012 US Chess Championship, when he defeated Gata Kamsky in the fourth round and led the tournament, briefly. However, he lost his next two games, one of which was to Robert Hess in a hard fought game. After that game, Kaidanov disclosed that he had changed his intended 10th move because a nearby game was playing the same line. He was worried about being accused of cheating. The worry was unfounded as there is no rule that forbids the unplanned mimicking of another game in plain sight.