The intermediate stage of completing a Rubik’s Cube involves correctly positioning the four edge pieces on the middle layer. This step follows the completion of the first layer (often the white face and corresponding edges) and precedes orienting and permuting the final, third layer. Successfully executing this stage results in the first two layers being entirely solved, providing a stable foundation for the cube’s ultimate resolution. This requires the mastery of algorithms designed to insert the middle-layer edges without disturbing the already solved first layer.
Achieving this stage is vital because it effectively reduces the remaining complexity of the puzzle. With the first two layers complete, the solver can then focus solely on the final layer, using a different set of algorithms. In the history of speedcubing, efficient methods for completing the middle layer have dramatically decreased solve times, allowing for increasingly complex algorithms to be employed for the final layer. It builds confidence and a sense of accomplishment as the puzzle rapidly converges to solution.
