Speedcubing
From Wikipedia, the free encyclopedia
Speedcubing (also known as speedsolving or spelled as two words, speed cubing or speed-cubing) is solving a Rubik's Cube as fast as possible. Here, solving is defined as performing a series of moves that result in each of the cube's faces being one single, solid color.
Regular cubes come in variations of 2x2x2, 3x3x3, 4x4x4, and 5x5x5. The current world record for a single solve of the 3x3x3 stands at 10.36 seconds, set by Edouard Chambon at the Belgian Open 2007 competition (February 25, 2007).[1][2]
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.
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[edit] History
The Rubik's Cube was invented in 1974 by Hungarian professor of architecture Ernő Rubik. 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. 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.[3] There have been two more World Championships since Budapest's 1982 competition, the first held in Toronto in 2003, and the second in Lake Buena Vista, Florida, in 2005.
[edit] Variations
The different sized cubes are usually referred to as:
- 2x2x2 - Rubik's Mini Cube or Pocket Cube
- 3x3x3 - Rubik's Cube
- 4x4x4 - Rubik's Revenge or Master Cube
- 5x5x5 - Rubik's Professor's Cube
The discussion below focuses on the regular 3x3x3 cube.
The 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. Another popular method is the Petrus system, named after its inventor, Lars Petrus, a method that is considered by some to be more intuitive than the structured Fridrich method. Other significant (though less widely-used) methods are various corners-first methods, simpler layer-by-layer approaches, and the Roux method.
[edit] Fridrich method
The Fridrich method first works to solve a cross-shaped arrangement of pieces on the first layer. The remainder of the first layer and the rest of the second layer are then solved together, in what are referred to as "corner-edge pairs". 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) with one algorithm, then, all of those cubies are permuted to their correct spots with a second algorithm.
[edit] Petrus method
The Petrus method first works to solve a 2x2x2 block of the cube. This block is then extended to a solved 2x2x3 block. The remaining two sides of the cube are then solved using only a few algorithms. 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!".[4] This method uses significantly fewer turns than a layers approach, and is often used as the basis for fewest moves competition solutions.
[edit] Roux method
The first step of the Roux method is the solution of a 3x2x1 block. The 3x2 rectangle is usually placed in the lower portion of the left face. The second step is to create another 3x2x1 on the right side. The remaining four corners are then solved, which leaves six edges and four centers that are solved in the last step. This method makes better 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 memorising as the Fridrich method, since all but the third step is rather easy to do. It doesn't require as many cube rotations as the Fridrich method, so it is easier to use active looking, i.e. while solving a collection of pieces and at the same time looking for pieces to solve.
[edit] 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). Currently, the official timer used in competition is the Stackmat timer. 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, and are not cheating in any way.
Official competitions are currently being held in several categories.
| Category | Cube Type |
|---|---|
| speedsolving | 2x2x2, 3x3x3, 4x4x4, 5x5x5 |
| one-handed solving | 3x3x3 |
| blindfolded solving | 3x3x3, 4x4x4, 5x5x5 |
| solving with feet | 3x3x3 |
| solving in fewest moves | 3x3x3 |
Competitions will often include events for speedsolving these other puzzles, as well:
[edit] World records
These are the world records for speedsolving the four types of cubes (as of February 26, 2007), as set during WCA-approved events.
| Cube type | Time (min:sec.csec) | Recordholder |
|---|---|---|
| 2x2x2 | 0:03.55 | Anthony Hsu |
| 3x3x3 | 0:10.36 | Edouard Chambon |
| 4x4x4 | 0:51.16 | Michael Fung |
| 5x5x5 | 1:44.47 | Frédérick Badie |
[edit] 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 affect 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.
- 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 e.g. in Corners First solving methods, 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).
- F2L
- First Two Layers.
- F2L method
- a method which solves the first and second layers simultaneously.
- LL
- Last Layer.
- method
- combination of algorithms that can be used to solve a cube.
- move
- a turn or double turn of one of the six faces of the cube (also opposite/parallel layers simultaneously).
- 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
- During a speedsolve one cubie comes 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.
- 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 move away from a solved state.
- UWR
- Unofficial World Record.
- WCA
- World Cube Association, the international governing body for official cube competitions.
- WR
- World Record.
[edit] See also
[edit] Notes
- ^ http://www.worldcubeassociation.org/results/regions.php
- ^ http://www.worldcubeassociation.org/results/c.php?i=BelgianOpen2007
- ^ http://www.speedcubing.com/events
- ^ http://lar5.com/cube/index.html
