Dylan O'Brien's performance as the Nogitsune was so outstanding that after finishing a scene the whole cast and crew clapped for him.
Peter says that chess is Stiles's game, not the game of a Japanese fox; in Stiles's head, he and the nogitsune are playing the game of Go, presumably the nogitsune's choice. Both are strategy games played on a board with a set of otherwise identical black and white pieces in which opponents take turns and attempt to capture one another's pieces, but in chess the player with the white pieces always goes first, while in Go it is the player with the black pieces.