"I have made a will leaving everything to my niece, Sonia Daviloff. You do not suggest—"
"I suggest nothing, but you have not seen your niece since she was a child. It would have been easy for any one to impersonate her."
Savaronoff seemed thunderstruck by the suggestion. Poirot went on easily.
"Enough as to that. I give you the word of warning, that is all. What I want you to do now is to describe to me the game of chess the other evening."
"How do you mean—describe it?"
"Well, I do not play the chess myself, but I understand that there are various regular ways of beginning—the gambit, do they not call it?"
Dr. Savaronoff smiled a little.
"Ah! I comprehend you now. Wilson opened Ruy Lopez—one of the soundest openings there is, and one frequently adopted in tournaments and matches."
"And how long had you been playing when the tragedy happened?"
"It must have been about the third or fourth move when Wilson suddenly fell forward over the table, stone dead."