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There are three possible outcomes of the game, white wins (1-0), black wins (0-1) or [[Draw|draw]] (1/2-1/2). Unfinished games may be [https://en.wikipedia.org/wiki/Adjournment#Chess adjudicated], which was common until the 80s in [[Tournamentsand Matches|computer chess tournaments]], for instance the adjudicated win of [[Cray Blitz]] against [[Schach|Schach 2.7]] during [[WCCC 1986]] <ref>[[Helmut Horacek]], ('''1986''') ''The Fifth World Computer Chess Championship Cologne, 1986'', Research Unit for Information Science and Artificial Intelligence, [[University of Hamburg]], from '''''Kings move''' Welcome to the 1989 AGT World Computer Chess Championship.'' pg 21, [http://archive.computerhistory.org/projects/chess/related_materials/text/3-1%20and%203-2%20and%203-3%20and%204-3.1989_WCCC/1989%20WCCC.062302028.sm.pdf pdf] from [[The Computer History Museum]]</ref> . [[Checkmate]] and [[Stalemate|stalemate]] finish the game immediately. Other occurrences usually require communication with the opponent and admission or adjudication of an arbiter instance (i.e. Tournament director), which in computer chess requires a protocol and/or interaction, like claiming a [[Repetitions|threefold repetition]] draw in over the board computer chess.

With the advent of operating systems with [https://en.wikipedia.org/wiki/Graphical_user_interface graphical user interfaces], also encouraged by additional input devices such as a [https://en.wikipedia.org/wiki/Mouse_%28computing%29 computer mouse] for asynchronous user interaction, the embedding of a chess engine with a classical CLI inside the [https://en.wikipedia.org/wiki/Event-driven_architecture event-driven architecture] of a graphical user interface became more difficult. Today, most programmers rely on external event driven [[GUI|graphical user interface]] applications using [https://en.wikipedia.org/wiki/Standard_streams standard streams] or [https://en.wikipedia.org/wiki/Pipeline_%28Unix%29 pipelines] to communicate with the GUI via protocols such as the [[Chess Engine Communication Protocol]] and the [[UCI|Universal Chess Interface]]. The external GUI application constitutes the MVC view and controller, and more or less even parts of a (redundant) game model (or even multi-game model), to make the GUI aware of its own game states to even make decisions on behalf of the engine, such as move selection from opening books and [[Endgame Tablebases|endgame tablebases]], draw claims and offers and to finally declare the game over. These game interacting features of the external GUI application in conjunction with certain protocols such as UCI by far exceeds what a pure chess user interface was initially designed for - controller and view only, enter legal moves and render the state of the game, which has become disputed issue in playing official [[Tournamentsand Matches|tournament]] games.