Speedcubing techniques

           The standard Rubik's Cube can be solved using a number of methods, not all of which are intended for speedcubing. Although some methods employ a layer-by-layer algorithm, other significant (though less widely-used) methods include corners-first methods, and the Roux method.

CFOP system

            CFOP (Cross - F2L - OLL - PLL) system also known as the Fridrich method was named after one of its inventors Jessica Fridrich who finished 2nd in the 2003 Rubik's Cube World Championships. It first works to solve a cross-shaped arrangement of pieces on the first layer. The remainder of the first layer and all of the second layer are then solved together in what are referred to as "corner-edge pairs" or slots. Finally, the last layer is solved in two steps — first, all of the cubies in the layer are oriented to form a solid color (but without the individual pieces being in their correct places on the cube). This step is referred to as orientation and usually is performed with a single set of algorithms known as OLL (Orientation of Last Layer). Then, all of those cubies are permuted to their correct spots. This is also usually performed as a single set of algorithms known as PLL (Permutation of Last Layer).

            The CFOP system is a widely-used speedcubing method. Its popularity stems from the speed at which it can be easily performed. Besides the first step, which can be planned during the customary 15-second inspection time, the entire solve of the cube consists of executing predefined algorithms based on the state of the cube.

 Intermediate cross

F2L part 1/2

F2L part 2/2

2 look OLL

2 look PLL

 

Petrus method

            The Petrus method, named after its inventor Lars Petrus, is considered by some people to be more intuitive than the structured Fridrich method. The Petrus method works by first solving a 2×2×2 block of the cube. This block is then extended to a solved 2×2×3 block. All edges are then oriented and then the first and second layers are completed. Next, the top corners are put in the right place and then the layer is oriented correctly (all stickers facing up) and finally the last edges are permuted (moved around). Lars Petrus developed this method to address what he felt were inherent inefficiencies in layer-by-layer approaches, which he explains in his method's tutorial: "When you have completed the first layer, you can do nothing without breaking it up. So you break it, do something useful, then restore it. Break it, do something, restore it. Again and again. In a good solution you do something useful all the time. The first layer is in the way of the solution, not a part of it!". This method is often used as the basis for fewest moves competition solutions.

Petrus method part 1/2

 Petrus method part 2/2

Roux method

             The first step of the Roux method is the formation of a 3×2×1 block. The 3×2×1 block is usually placed in the lower portion of the left layer. The second step is to create another 3×2×1 on the opposite layer. The remaining four corners are then solved, which leaves six edges and four centers that are solved in the last step.

           This method makes more efficient use of the standard 15 second inspection time, since one can plan the solution of 5 pieces rather than 4 for the Fridrich and Petrus method. It also isn't as dependent on algorithm memorization as the Fridrich method, since all but the third step is done with intuition as opposed to predefined sets of algorithms. Because of this, however, the solve may not be executed as quickly as a solve done with the Fridrich method. It doesn't require as many cube rotations as the Fridrich method, so it is easier to look ahead while solving i.e. solving a collection of pieces and at the same time looking for the solution to the next step.

Roux method tutorial part 1/1

Corners-first method

            This method involves solving the corners then finishing the edges with slice turns. Corners-first solutions were common in the 1980s, with one of the most popular methods that of 1982 world champion Minh Thai. Currently corners-first solutions are less common among speedsolvers. The best corners first method was created in the cube craze by Dutch cuber Marc Waterman. He averaged 16 seconds in the mid-late 80s. First, build a face on the left. Then, solve the remaining corners. Next, solve two right edges and place one remaining right edge in the right layer OR solve three right edges. Then, solve the last right edge(s) and orient middle edges simultaneously. Finally, permute middle edges. This method only requires the memorization of around 7 algorithms.

Corners-first method tutorial part 1/1

 ZZ method

             ZZ is a modern speedcubing method, originally proposed by Zbigniew Zborowski in 2006. The method was designed specifically to achieve high turning speed by focusing on move ergonomics. The initial pre-planned step is called EOLine, and is the most distinctive hallmark of the ZZ method. It involves orienting all edges while placing two opposite down-face edges. The next step solves the remaining first two layers using only left, right and top face turns. On completion of the first two layers, the last layer's edges are all correctly orientated because of edge pre-orientation during EOLine. The last layer may be completed using a number of techniques including those used in the Fridrich method. An expert variant of this method (ZZ-a) allows the last layer to be completed in a single step with an average of just over 12 moves and knowledge of 177 algorithms.

ZZ method tutorial part 1/2

ZZ method tutorial part 2/2