Rainsford and Zaroff are playing a game of strategy like chess, where intelligence and cunning are required and you need to think several moves ahead to win.
Chess is a game of strategy. That means that you need to have a plan. You need to think about not just the move you are making, but several moves at a time. This is definitely true in Rainsford and Zaroff’s case. Zaroff definitely has the advantage because he designed the board. Both Rainsford and Zaroff are expert hunters, or expert chess players. Rainsford has written books on the subject, and Zaroff is a rich man who has hunted all around the world. Zaroff tells Rainsford that he has read his books on hunting.
… I recognized your name. You see, I read all books on hunting published in English, French, and Russian. I have but one passion in my life, Mr. Rains. ford, and it is the hunt."
In many ways, the playing field is un-level. Zaroff designed the island, and Rainsford is unfamiliar with it—unlike a real chess board. However, this could be like two people who do not have the same familiarity with chess strategies. Also, Rainsford fell off of his boat and was not prepared to play. He was forced to play what Zaroff calls “Outdoor chess.”
"…Again you score. I think, Mr. Rainsford, Ill see what you can do against my whole pack. I'm going home for a rest now. Thank you for a most amusing evening.
However, Rainsford has one advantage over Zaroff. Rainsford knows he is fighting for his life, and Zaroff does not. Rainsford kills Zaroff when he loses. Zaroff did not know Rainsford was going to do that. He did know that Rainsford was cunning prey, but by that he meant difficult to kill, not difficult to evade.
In a chess game, the opponents often prefer someone they can match wits against. Good chess plays don’t just want to beat someone—they want to beat someone they can brag about beating. They want to beat a worthy opponent, someone who gave them some trouble. They want to beat someone who is good at chess, and someone who was not easy to beat. This is why Zaroff is so excited to see Rainsford on his island. He finally has some worthy competition.