We present a study on three-dimensional chocolate bar games that are variants of three-pile nim. A three-dimensional chocolate bar is a three-dimensional array of cubes containing a bitter cubic box in some parts of the bar. Two players take turns to cut the bar horizontally or vertically along the grooves into two parts and eat the one without the bitter part. The player that manages to leave the opponent with a single bitter block wins the game. The authors studied \(\mathcal {P}\) -positions of this game, where \(\mathcal {P}\) -positions are positions of the game from which the previous player (the player who will play after the next player) can force a win, as long as he plays correctly at every stage. The authors present some sufficient conditions for the case in which the position (p, q, r) is a \(\mathcal {P}\) -position if and only if \((p-1) \oplus (q-1) \oplus (r-1)\) , where p, q, and r are the length, height, and width of the chocolate bar, respectively.