Rubik's Cube being speedsolved. The Rubik's Cube is a Mechanical puzzle invented in 1974 by Hungarian Sculptor and Professor of Architecture Ernő Rubik

As can be seen from these two pictures, often the cube will be manipulated very quickly.

Speedcubing (also known as speedsolving, speed cubing or speed-cubing) is the activity of solving a Rubik's Cube or related puzzle as quickly as possible. The Rubik's Cube is a Mechanical puzzle invented in 1974 by Hungarian Sculptor and Professor of Architecture Ernő Rubik Here, solving is defined as performing a series of moves that transforms an incomplete cube into a state where each of the cube's six faces is one single, solid color.

Regular cubes are sold commercially in variations of 2x2x2, 3x3x3, 4x4x4, and 5x5x5. Variations of the puzzle have been designed with as many as 11 layers, but the largest denomination cube that has been physically produced is a 7x7x7. ^[1][2] The current world record for a single solve of the 3x3x3 stands at 8. 72 seconds, set by Yu Nakajima at the Kashiwa Open competition (Japan) on May 5, 2008. is a Japanese Rubik's Cube solver Yu holds the current World record for average (11 ^[3][4]

Speedcubing is the most prominent activity of the international Rubik's Cube community. Members come together to hold competitions, work to develop new solving methods, and seek to perfect their technique. As a part of the community, puzzle builders try to invent new forms of permutation puzzles.

History

The Rubik's Cube was invented in 1974 by Hungarian professor of architecture Ernő Rubik. The Rubik's Cube is a Mechanical puzzle invented in 1974 by Hungarian Sculptor and Professor of Architecture Ernő Rubik Ernő Rubik (born July 13, 1944) is a Hungarian Inventor, sculptor and professor of Architecture. A widespread international interest in the cube began in 1980, which soon developed into a global craze. On June 5, 1982, the first world championship was held in Budapest. Events 70 - Titus and his Roman Legions breach the middle wall of Jerusalem in the Siege of Jerusalem Year 1982 ( MCMLXXXII) was a Common year starting on Friday (link displays the 1982 Gregorian calendar) The height of the craze began to fade away after 1983, but with the advent of the Internet, sites relating to speedcubing began to surface. Simultaneously spreading effective speedsolving methods and teaching people new to the cube to solve it for the first time, these sites brought in a new generation of cubers, created a growing international on-line community, and raised the profile of the art. Twenty years after the first World Championship, the 2002 Dutch Open competition was the first in a new wave of organized speedcubing events, which include regular national and international competitions. ^[5] There have been three more World Championships since Budapest's 1982 competition, the first held in Toronto in 2003, the second in Lake Buena Vista, Florida in 2005, and after 25 years the tournament returned to Budapest in 2007. Toronto (təˈrɒntoʊ colloquially pronounced or) is the largest city in Canada and is the provincial capital of Ontario Lake Buena Vista is a city in Orange County, Florida, United States.

Solving Methods

The standard Rubik's cube can be solved using a number of methods, not all of which are suited for speedcubing. One of the most-used speedcubing methods is the Fridrich method, named after its inventor, Jessica Fridrich, who finished 2nd in the 2003 Rubik's Cube World Championships. Fridrich Method is one of the most commonly used methods in speedsolving a Rubik's Cube. Jessica Fridrich is the inventor of the most commonly-used method for speed-solving the Rubik's Cube, better known as Speedcubing. Another popular method is the Petrus system (also commonly known as the "Lars Method"), named after its inventor, Lars Petrus, a method that is considered by some to be more intuitive than the structured Fridrich method. Lars Petrus (born in 1960 made his name as an internationally accomplished speed cuber in 1982 when he became the national champion of Other significant (though less widely-used) methods are various corners-first methods, simpler layer-by-layer approaches, and the Roux method.

Below are overviews of some commonly used speedcubing methods. For a more in-depth discussion of a particular method, see the appropriate article.

Fridrich method

The Fridrich method first works to solve a cross-shaped arrangement of pieces on the first layer. Fridrich Method is one of the most commonly used methods in speedsolving a Rubik's Cube. 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 algorithm 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 algorithm known as PLL (Permutation of Last Layer).

The Fridrich method 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.

Petrus method

The Petrus method works by first solving a 2x2x2 block of the cube. This block is then extended to a solved 2x2x3 block. All edges are then oriented, and then the remaining two sides of the cube are then solved using only a few algorithms. 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!". [1] This method uses significantly fewer turns than a layers approach, and is often used as the basis for fewest moves competition solutions.

Roux method

The first step of the Roux method is the formation of a 3x2x1 block. The 3x2x1 block is usually placed in the lower portion of the left layer. The second step is to create another 3x2x1 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 memorizing 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.

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. Minh Thai was a sixteen-year-old Vietnamese high school student from Los Angeles when he won the first world championship on June 5, 1982 in Budapest Currently corners-first solutions are less common among speedsolvers, though popular solutions for the 2x2x2 are based on these methods. The Pocket Cube (also known as the Mini Cube) is the 2×2×2 equivalent of a Rubik's Cube.

Competitions

According to the World Cube Association, competitors (in the same round) must solve cubes that are scrambled using a consistent algorithm (as in, every competitor solves the same scramble). The World Cube Association (commonly abbreviated as WCA) is an organization that regulates and holds Rubik's Cube competitions Currently, the official timer used in competition is the StackMat timer. Stackmat timers are the official timing device for speed stacking and Speedcubing. This device has touch-sensitive pads that are triggered by the speedcuber lifting their hands to start the time and placing their hands back on the pads after releasing the puzzle to stop the time. In addition to the electronic timer, there are human judges with stopwatches, who act as a back-up in case the timer doesn't work properly. These judges also ensure that the competitors are following competition regulations.

Official competitions are currently being held in several categories.

Competitions will often include events for speedsolving these other puzzles, as well:

• Megaminx
• Pyraminx
• Rubik's Clock
• Rubik's Magic
• Square-1

World records

These are the world records for speedsolving the four types of cubes as set during WCA-approved events. The Pocket Cube (also known as the Mini Cube) is the 2×2×2 equivalent of a Rubik's Cube. The Rubik's Cube is a Mechanical puzzle invented in 1974 by Hungarian Sculptor and Professor of Architecture Ernő Rubik The Rubik's Revenge is the 4×4×4 version of Rubik's Cube. Invented by Péter Sebestény the Rubik's Revenge was nearly called the Sebestény Cube until a somewhat last-minute The Professor's Cube is a mechanical Puzzle, a 5×5×5 version of the Rubik's Cube. The Rubik's Cube is a Mechanical puzzle invented in 1974 by Hungarian Sculptor and Professor of Architecture Ernő Rubik The Rubik's Cube is a Mechanical puzzle invented in 1974 by Hungarian Sculptor and Professor of Architecture Ernő Rubik The Rubik's Revenge is the 4×4×4 version of Rubik's Cube. Invented by Péter Sebestény the Rubik's Revenge was nearly called the Sebestény Cube until a somewhat last-minute The Professor's Cube is a mechanical Puzzle, a 5×5×5 version of the Rubik's Cube. The Rubik's Cube is a Mechanical puzzle invented in 1974 by Hungarian Sculptor and Professor of Architecture Ernő Rubik The Rubik's Cube is a Mechanical puzzle invented in 1974 by Hungarian Sculptor and Professor of Architecture Ernő Rubik The Megaminx is a Dodecahedron -shaped puzzle similar to the Rubik's Cube. The Pyraminx is a Tetrahedron -shaped puzzle similar to the Rubik's Cube. Rubik's Clock is a Mechanical puzzle invented and Patented by Christopher C Rubik's Magic, like Rubik's Cube, is a mechanical Puzzle invented by the Hungarian sculptor and professor of Architecture Ernő Rubik The Square One, also known as Back to Square One and Cube 21, is a puzzle similar to the Rubik's Cube.

Lubrication

Some speedcubers will lubricate their cubes to prevent wrist and finger injury. Erik Akkersdijk (born October 7, 1989 in Enschede, The Netherlands) is a Dutch Rubik's Cube solver Lubricating the cube also allows it to be manipulated more quickly than a non-lubed cube. The WCA allows lubrication for WCA-sanctioned competitions. Usually, the lubricant's main ingredient is polysiloxane. Silicones are largely inert compounds with a wide variety of forms and uses

ABS, the main plastic in Rubik's cubes, should not be lubricated with lubricants containing any of the following:

• Methylene chloride, often used for welding ABS plastic
• Acetone, a good solvent for ABS plastic
• WD-40, incompatible with ABS plastic due to white spirit (also known as Stoddard solvent) content

Checking a lubricant's MSDS is often helpful in identifying cube-damaging ingredients. Acrylonitrile butadiene styrene or ABS, ( Chemical formula (C8H8· C4H6·C3H3Nn is Dichloromethane ( DCM) or methylene chloride is the Chemical compound with the formula CH2Cl2 Acetone (also known as propanone, dimethyl ketone, 2-propanone, propan-2-one and β-ketopropane) is a colorless mobile flammable WD-40 is the Trademark name of a widely-used Penetrating oil (and cleaner, Dielectric and anti- Corrosion) spray Solution White spirit, also known as Stoddard solvent, is a Paraffin -derived clear transparent liquid which is a common organic Solvent used in painting and A material safety data sheet ( MSDS) is a form containing data regarding the properties of a particular substance

Terminology

Here are some definitions generally used by the speedcubing community. For a more complete list of speedcubing terminology, see Shotaro "Macky" Makisumi's glossary.

Algorithm 

A predefined sequence of moves used to effect a specific change on the cube. Often referred to as alg.

BLD 

Blindfold solving, i. e. memorize, blindfold, then solve.

Center piece 

one of the six centers of the faces of the cube. The centers never move relative to each other on an NxNxN cube, where N is odd.

CLL 

Corners of Last Layer. This is the first of two steps to solve the last layer of the cube. In the process, edges may not be unoriented. This is used in Corners First methods for the last layer, in which the first all corners are solved, followed by the edges (see: ELL).

Corner piece 

One of the 8 corner pieces.

Cubie 

One of the 20 mechanically independent pieces that make up the cube. The cubies do not include the center pieces, nor the central axis to which they are attached.

Cycle 

To rotate pieces' positions on the cube. E. g. a 3-cycle would make cubie set A-B-C become C-A-B.

DNF 

Did Not Finish, used in competition e. g. when a piece pop occurs and the competitor decides not to continue the solving of the puzzle.

DNS 

Did Not Solve, used in competition when the competitor was unable to solve the puzzle in the required time.

Edge piece 

One of the 12 edge pieces.

ELL 

Edges of Last Layer. The second of two steps to solve the last layer of the cube, solving the edge pieces without disturbing the orientation of the corner pieces (see: CLL).

F2B 

First two blocks.

F2L 

First two layers.

F2L method 

a method which solves the first and second layers simultaneously.

LL 

Last Layer.

Method 

A combination of steps that can be used to solve a cube.

Move 

A turn or double turn of one of the six faces or three slices of the cube.

N-look, also known as X-Look 

refers to the number of algorithms needed to complete a step in a particular solving method, often the last layer, e. g. '4-look LL'.

OLL 

Orient Last Layer, usually used in reference to the respective step of the Fridrich method.

Orient 

To flip or twist pieces so they turn 'in-place'.

PB 

Personal Best - personal record time to solve a puzzle. This can either be a single attempt or a trimmed average, depending on context.

Permute 

swap or cycle two or more pieces.

PLL 

Permute Last Layer. Usually used in reference to the respective step of the Fridrich method, in which case it would follow the OLL step.

Pop 

When, during a speedsolve, one or more cubies come out of the puzzle. Also known as piece pop.

Prime 

A counter-clockwise move popularly denoted with a ', e. g. 'R Prime', denoted as R', R-, R^-1, Ri. Also known as "inverse" or "inverted".

Slice 

The four center pieces and four edge pieces between two opposite faces of the cube.

Two-Second Penalty 

A penalty of 2 seconds which is added to a solving time in competition when the cube is placed back on the timing pad with one or more misaligned faces.

UWR 

Unofficial World Record.

WCA 

World Cube Association, the international governing body for official cube competitions. The World Cube Association (commonly abbreviated as WCA) is an organization that regulates and holds Rubik's Cube competitions

WR 

World Record.

See also

• Rubik's Cube
• Jessica Fridrich
• Lars Petrus
• World Cube Association

Notes

External links

• Speed Cube Solution Guide - with pictures
• speedcubing.com - Speedcubing informational and Unofficial World Records site
• Speedcubing Discussion Forum
• Fridrich method
• Petrus method
• Roux method