Learn about/How to Solve Rubik's Cube

The Rubik's Cube is a 3-D combination puzzle originally invented in 1974 by Hungarian sculptor and professor of architecture Ernő Rubik. Originally called the Magic Cube. The cube was released internationally in 1980 and became one of the most recognized icons in popular culture. It won the 1980 German Game of the Year special award for Best Puzzle. As of January 2009, 350 million cubes had been sold worldwide, making it the world's bestselling puzzle game and bestselling toy. The Rubik's Cube was inducted into the US National Toy Hall of Fame in 2014.

On the original classic Rubik's Cube, each of the six faces was covered by nine stickers, each of one of six solid colors: white, red, blue, orange, green, and yellow. Some later versions of the cube have been updated to use colored plastic panels instead, which prevents peeling and fading. Since 1988, the arrangement of colors has been standardized with white opposite yellow, blue opposite green, and orange opposite red, and the red, white, and blue arranged clockwise in that order. On early cubes, the position of the colors varied from cube to cube. An internal pivot mechanism enables each face to turn independently, thus mixing up the colors. For the puzzle to be solved, each face must be returned to have only one color. Similar puzzles have now been produced with various numbers of sides, dimensions, and stickers, not all of them by Rubik.

A standard Rubik's Cube measures 5.6 centimetres (2+1⁄4 in) on each side. The puzzle consists of 26 unique miniature cubes, also known as "cubies" or "cubelets". Each of these includes a concealed inward extension that interlocks with the other cubes while permitting them to move to different locations. However, the centre cube of each of the six faces is merely a single square façade; all six are affixed to the core mechanism. These provide structure for the other pieces to fit into and rotate around. Hence, there are 21 pieces: a single core piece consisting of three intersecting axes holding the six centre squares in place but letting them rotate, and 20 smaller plastic pieces that fit into it to form the assembled puzzle.

Each of the six centre pieces pivots on a screw (fastener) held by the centre piece, a "3D cross". A spring between each screw head and its corresponding piece tensions the piece inward, so that collectively, the whole assembly remains compact but can still be easily manipulated. The screw can be tightened or loosened to change the "feel" of the Cube. Newer official Rubik's brand cubes have rivets instead of screws and cannot be adjusted. However, Old Cubes made by the Rubik's Brand Ltd. and from dollar stores do not have screws or springs, all they have is a plastic clip to keep the centre piece in place and freely rotate.

The Cube can be taken apart without much difficulty, typically by rotating the top layer by 45° and then prying one of its edge cubes away from the other two layers. Consequently, it is a simple process to "solve" a Cube by taking it apart and reassembling it in a solved state.

Possibilities

The puzzle was originally advertised as having "over 3,000,000,000 (three billion) combinations but only one solution". Depending on how combinations are counted, the actual number is significantly higher. This is how we have calculated all the possible permutation of the cube without disassembly,

which is approximately 43 quintillion. To put this into perspective, if one had one standard-sized Rubik's Cube for each permutation, one could cover the Earth's surface 275 times, or stack them in a tower 261 light-years high.

Algorithms

In Rubik's cubers' parlance, a memorised sequence of moves that has a desired effect on the cube is called an "algorithm". This terminology is derived from the mathematical use of algorithm, meaning a list of well-defined instructions for performing a task from a given initial state, through well-defined successive states, to a desired end-state. Each method of solving the Cube employs its own set of algorithms, together with descriptions of what effect the algorithm has, and when it can be used to bring the cube closer to being solved.

Many algorithms are designed to transform only a small part of the cube without interfering with other parts that have already been solved so that they can be applied repeatedly to different parts of the cube until the whole is solved. For example, there are well-known algorithms for cycling three corners without changing the rest of the puzzle or flipping the orientation of a pair of edges while leaving the others intact. Some algorithms do have a certain desired effect on the cube (for example, swapping two corners) but may also have the side-effect of changing other parts of the cube (such as permuting some edges). Such algorithms are often simpler than the ones without side effects and are employed early on in the solution when most of the puzzle has not yet been solved and the side effects are not important. Towards the end of the solution, the more specific (and usually more complicated) algorithms are used instead.

Speedcubing competitions

Speedcubing (or speedsolving) is the practice of trying to solve a Rubik's Cube in the shortest time possible. There are a number of speedcubing competitions that take place around the world.

A speedcubing championship organised by the Guinness Book of World Records was held in Munich on 13 March 1981. The contest used standardised scrambling and fixed inspection times, and the winners were Ronald Brinkmann and Jury Fröschl with times of 38.0 seconds. The first world championship was the 1982 World Rubik's Cube Championship held in Budapest on 5 June 1982, which was won by Minh Thai, a Vietnamese student from Los Angeles, with a time of 22.95 seconds.

The World Cube Association maintains a history of world records. In 2004, the WCA made it mandatory to use a special timing device called a Stackmat timer.

In addition to the main 3x3x3 event, the WCA also holds events where the cube is solved in different ways:

• Blindfolded solving
• Multiple Blindfolded solving, or "multi-blind", in which the contestant solves any number of cubes blindfolded in a row
• Solving the cube using a single hand, or one handed solving
• Solving the cube in the fewest possible moves

Tutorial

Want to test your brain power and finally solve a cube, here's a how to solve video by @JPerm