At the end of Orwell's 1984, Winston was a regular customer of the Chestnut Tree Café. He would go there every day, and the waiters would always bring him a chessboard and the current issue of the Times, which contained a new chess problem every day.
Now, chess requires deep thinking. Isn't this something that the Party would never want?
Yet, the game was allowed. Actually, considering that the newspaper published a new problem every day, it could be said that playing chess was not only allowed, but even encouraged. And the problems weren't trivial: on the day on which the last chapter is set, the problem was a "tricky" ending.
Doesn't it contradict the spirit of everything that the Party does?
Newspeak, for example, is meant to be really simple, in order to discourage complex thought. Syme explains that
In fact there will be no thought, as we understand it now. Orthodoxy means not thinking - not needing to think. Orthodoxy is unconsciousness.
—1984, Part 1, chapter V
Considering the length the Party goes to in order to make people incapable of thinking, why is the game of chess allowed?