Conversation so far:
how much time is given in a chess tournament
International chess has a standard time control of 40 moves in 2 hours and then an extra hour to reach move 60.
What instrument is used to measure time in chess tournament?
Chess clocks are used in chess and other two-player games where the players move in turn.

Question: When was the device first used?
Self-contained rewrite: When the chess clock first used in a tournament?