In the short story The Chess Problem (later chapter 11 of The Big Four), Ivan is the manservant of the chess master Dr Savaronoff. According to Captain Hastings, Ivan had a peculiarly wooden face. "It seemed impossible to believe that the impassive countenance could ever display emotion." For a while, Poirot suspected that Ivan was Number Four in disguise and possibly the murderer of Gilmour Wilson but it later turned out that he was entirely innocent.