The psychic could read the mind of the opponent, who would be contemplating several moves in advance. If the opponent’s thinking is dominated by a particular imagined response to the move that they eventually make then the psychic could assume that would be a good move.
Alternatively, the psychic could hire an expert player to watch the match and concentrate on the best moves for the psychic to make.
Even without being psychic, a person could challenge the world’s two best chess players to play games against them at the same time (I saw this on a television drama). What they did was to observe the opening move of one player and then copy it in the second game. Then they waited for a response and copied it in the first game. Continuing in that way, the two champs were in effect playing each other. The challenger would either win one game and lose the other or play to a draw in both of them.
I believe there are some psychics, but that’s not how they work. They can’t simply focus on someone’s mind and get the answers they want. Doesn’t work that way at all.
@smudges Indeed. Different psychics have different abilities,both in fiction and in reality. None of the real ones I know anything about can simply read anything in another’s mind, nor can they reliably predict specific futures, such as a chess move.
There are some fictional ones who might be able to do that, but only in particularly far-out fiction. e.g. Star Wars Jedi, but even they fail to predict things sometimes.