Chess.com indicates: "The middlegame is, as its name implies, the middle part of a chess game, after the opening and before the endgame. The middlegame is often the most complex and important phase of the game, and most games are decided here. Even if an endgame is reached, "winning endings" and "drawn endings" are usually created in the middlegame."<ref>[https://www.chess.com/terms/chess-middlegame Chess middlegame]</ref>