1. A game played face-to-face with the opponent, as opposed to a remote opponent as in online chess or correspondence chess.

2. Analysis carried out during a game in real time (not necessarily a face-to-face game) as opposed to during preparation. Finding accurate moves over the board is harder than finding them with computer assistance in one's own time. "I looked up the gambit Smith played and there's a line that refutes it, but I couldn't find it over the board."

Abbr. OTB.