Speedcubing

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Erik Akkersdijk solving a 3×3×3 Rubik's Cube in 10.50 seconds.
File:Speedcubing-Twilightsojourn.jpg
A speedsolver completing a 3×3×3 Rubik's Cube.

Speedcubing (also known as speedsolving) is the activity of solving a variety of twisty puzzles, the most famous being the Rubik's Cube, as quickly as possible. For most puzzles, solving entails performing a series of moves that alters a scrambled puzzle into a state in which every face of the puzzle is a single, solid color. Some puzzles have different requirements to be considered solved, such as the Clock, for which all the dials must be moved into the 12 'o clock position.[1]

Most cubes are sold commercially in variations of 2×2×2, 3×3×3, 4×4×4, 5×5×5, 6×6×6, and 7×7×7, although variations of the puzzle have been designed with as many as 17 layers.[2] The current world record for a single solve of the 3×3×3 in competition is 4.90 seconds, set by Lucas Etter in November 2015 at the River Hill Fall 2015 competition in Clarksville, Maryland.[3]

Speedcubing is a popular activity among the international Rubik's Cube community, or cubers. 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 and modders try to invent new forms of combination puzzles.

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, Hungary. 19 people competed in the event and the American Minh Thai won with a single solve time of 22.95 seconds. Other notable attendees include Jessica Fridrich and Lars Petrus, two people who would later be influential in the development of solving methods and the speedcubing community. The height of the Rubik's Cube 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 online community, and raised the profile of the art. People prominent in this online community, such as Ron Van Bruchem, Tyson Mao, Chris Hardwick, and Ton Dennenbroek, eventually wanted to meet in person and compete, so twenty years after the first world championship they orchestrated a second one in Toronto in 2003, and another smaller competition in the Netherlands later that same year. This revival of competition sparked a new wave of organized speedcubing events, which include regular national and international competitions.[4] There were twelve competitions in 2004, 58 more from 2005 to 2006, over 100 in 2008, and over 450 in 2014, with more happening every year. There have been seven more World Championships since Budapest's 1982 competition, which are traditionally held every other year, with the most recent in São Paulo, Brazil, in 2015. This new wave of speedcubing competitions have been and still are organised by the World Cube Association (WCA), founded by Ron van Bruchem.

Solving methods

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 system and algorithms, other significant (though less widely used) methods include corners-first methods, and the Roux method. CFOP, Roux, ZZ and Petrus are often referred to as the "big four" methods, as they are the most popular and fastest.

CFOP method

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Main article: CFOP Method

The CFOP (Cross - F2L - OLL - PLL) method, also known as the Fridrich Method, was named after one of its inventors, Jessica Fridrich, who finished second in the 2003 Rubik's Cube World Championships. While it is known as the Fridrich method, its origins are actually credited to David Singmaster, who was one of the first to publish a layer by layer method of solving in 1980,[5] and Guus Razoux Schultz, who built upon this and developed a more efficient system for the first two layers (F2L).[6] Jessica Fridrich then finished developing the method and published it online in 1997,[7] an event that was very influential in the revival of competitive speedcubing. The first step of the method is 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 pieces in the layer are oriented to form a solid color (but without the individual pieces always being in their correct places on the cube). This step is referred to as orientation and is usually performed with a single set of algorithms known as OLL (Orientation of Last Layer). Then, all of those pieces 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 method is a widely used speedcubing method. Its popularity stems from the speed at which it can be easily performed. Many advanced speedcubers have also learned additional sets of algorithms for the last layer, such as Corners of Last Layer (COLL), which orients and permutes the corners when the edges are oriented.

Roux method

The Roux method was invented by French speedcuber Gilles Roux. The first step of the Roux method is to form a 3×2×1 block placed in the lower portion of the left layer. The second step is to create another 3×2×1 on the opposite side. The remaining four corners are then solved using a set of algorithms known as CMLL (Corners of the Last Layer, without regard to the M-slice), which leaves six edges and four centers that are solved in the last step.

This method is not as dependent on algorithm memorization as the CFOP method, since all but the third step is done with intuition as opposed to predefined sets of algorithms. The Roux method can more easily be performed without rotations (unlike the CFOP method) which means it is easier to look ahead (solving a collection of pieces while at the same time looking for the solution to the next step) while solving.

ZZ method

The ZZ method, short for Zbigniew Zborowski, 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, and is the combination of a block-building method and a layer-by-layer method. 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 aligned with their corresponding centers. The next step solves the remaining first two layers using only left, right, top and bottom face turns, one of the advantages of ZZ. On completion of the first two layers, the last layer's edges are all correctly oriented because of edge pre-orientation during EOLine. The last layer may be completed using a number of techniques including those used in the CFOP 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 at least 177 algorithms.[8]

Petrus method

The Petrus method, named after its inventor Lars Petrus, is considered to be more intuitive than the structured CFOP method. The first step of the Petrus method is to solve 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 the first and second layers are completed. Next, the top corners are put in the right place and 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. This method is often used as the basis for fewest moves competition.

Corners-first methods

Corners-first methods involve 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. Dutch cuber Marc Waterman created a corners-first method in the cube craze, and averaged 16 seconds in the mid-late 1980s.

Competitions

File:Estonian Open 2009 - Anssi Vanhala.JPG
Anssi Vanhala solving a 3×3×3 Rubik's Cube with his feet in 36.72 seconds, at the 2009 Estonian Open.

World Cube Association

Since 2003, speedcubing competitions have been held regularly. The World Cube Association (WCA) was formed in 2004 to govern all official competitions. For a competition to be official, it must be approved by the WCA and follow the WCA regulations. Included in the regulations is the necessity of having one or more WCA delegate in attendance. A delegate's main role is to ensure all regulations are followed during the competition. Once the competition has finished, the results are uploaded on to the WCA website.

Format

The majority of puzzles are held using an average of 5 formats. This involves the competitor solving 5 times in the round; the fastest and slowest solve are disregarded and the mean of the remaining 3 is used. The events 6x6x6, 7x7x7, and Rubik's Cube with feet are ranked by mean of 3. This is the same but only 3 solves are done, and no solves are disregarded when calculating the mean. 3x3x3 blindfolded and fewest moves challenge are held either by mean of 3 or best of 3. 4x4x4 blindfolded, 5x5x5 blindfolded and multiple blindfolded are held using best of 1, 2 or 3, depending on the competition. Occasionally an event is held using an uncommon format, for example best of 3 for 3x3x3.

When a round begins, competitors hand in the puzzle they will use. Puzzles are scrambled using a computer-generated scramble. Each round, five, three or one (depending on the format, mentioned above) scrambles are used. Every competitor in the round will receive each scramble once. Before starting a solve, a competitor has up to 15 seconds to inspect the puzzle (inspection is removed for blindfolded events). This is monitored by a judge with a stopwatch. Once the solve is complete, the judge records the time on the competitor's scorecard and it is signed by both. If the puzzle is unsolved and the timer is stopped, the time is recorded as "DNF" (did not finish). There are also numerous reasons why the solve can receive a two second addition to the solve time, such as a face being more than 45 degrees off, or the competitor going over the allowed inspection time. A competitor can also receive an extra solve to replace the one just completed, for example having a timer malfunction or being deliberately distracted by another person.

Currently, the official timer used in competitions is the StackMat timer. This device has touch-sensitive pads that are triggered by the user lifting both of their hands to start the time and placing both their hands back on the pads after releasing the puzzle to stop the timer.

Official competitions are currently being held in several categories.

Category Cube Type
SpeedSolving 2×2×2, 3×3×3, 4×4×4, 5×5×5, 6×6×6, 7×7×7
Blindfolded Solving 3×3×3, 4x4x4, 5x5x5
Multiple-Blindfolded Solving 3×3×3
One Handed Solving 3×3×3
Solving with Feet 3×3×3
Solving in Fewest Moves 3×3×3
File:Megaminx, Estonian Open 2011.jpg
Speedsolvers solving Megaminxes at the 2011 Estonian Open.

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

World Rubik's Cube Championships

The WCA organizes the World Rubik's Cube Championship as the main international competition once every two years. The latest championship was held in São Paulo, Brazil, from July 17-19, 2015.

Championship Year Host Dates Nations Puzzles Events Winner Winning time(s) Ref
I 1982 Hungary Budapest June 5 19 1 1 Minh Thai 22.95 [9]
II 2003 Canada Toronto August 23–24 15 9 13 Dan Knights 20.00 [10]
III 2005 United States Lake Buena Vista November 5–6 16 9 15 Jean Pons 15.10 [11]
IV 2007 Hungary Budapest October 5–7 28 10 17 Yu Nakajima 12.46 [12]
V 2009 Germany Düsseldorf October 9–11 32 12 19 Breandan Vallance 10.74 [13]
VI 2011 Thailand Bangkok October 14–16 35 12 19 Michał Pleskowicz 8.65 [14]
VII 2013 United States Las Vegas July 26–28 35 10 17 Feliks Zemdegs 8.18 [15]
VIII 2015 Brazil São Paulo July 17–19 37 11 18 Feliks Zemdegs 7.56 [16]

World records

The following are the official speedcubing world records that are approved by the World Cube Association.[17]

Note: For averages of 5 solves, the best time and the worst time are dropped, and the mean of the remaining 3 solves is taken. When only 3 solves are done, the mean of all 3 is taken as normal.

Event Type Result (Min:Sec.100ths) Person Competition Result Details (Min:Sec.100ths)
2×2×2 Single 00:00.58 United States Rami Sbahi Canadian Open 2015
Average 00:01.51 United States Lucas Etter Music City 2015 00:01.24 / 00:01.69 / 00:02.21 / 00:01.45 / 00:01.39
3×3×3 Single 00:04.90 United States Lucas Etter River Hill Fall 2015
Average 00:06.54 Australia Feliks Zemdegs Melbourne Cube Day 2013 00:06.91 / 00:06.41 / 00:06.25 / 00:07.30 / 00:06.31
4×4×4 Single 00:21.54 Australia Feliks Zemdegs China Championship 2015
Average 00:26.03 Germany Sebastian Weyer German Nationals 2014 00:26.06 / 00:27.08 / 00:26.36 / 00:25.68 / 00:24.86
5×5×5 Single 00:46.97 Australia Feliks Zemdegs Melbourne Cube Day 2015
Average 00:50.15 Australia Feliks Zemdegs Melbourne Cube Day 2015 00:52.43 / 00:49.88 / 00:48.15 / 00:55.13 / 00:46.97
6×6×6 Single 01:33.55 United States Kevin Hays Indiana 2015
Average 01:43.83 Australia Feliks Zemdegs Melbourne Cube Day 2015 1:44.61 / 1:44.02 / 1:42.86
7×7×7 Single 02:23.55 Australia Feliks Zemdegs World Championship 2015
Average 02:30.14 Australia Feliks Zemdegs Melbourne Cube Day 2015 2:29.53 / 2:24.18 / 2:36.72
Megaminx Single 00:37.58 Korea Yu Da-Hyun Spring Comes 2015
Average 00:42.89 Korea Yu Da-Hyun Asian Championship 2014 00:47.53 / 00:43.88 / 00:40.16 / 00:43.15 / 00:41.65
Pyraminx Single 00:01.32 United States Drew Brads Lexington Fall 2015
Average 00:02.52 United States Drew Brads Lexington Fall 2015 00:02.56 / 00:01.32 / 00:03.17 / 00:02.54 / 00:02.46
Square-1 Single 00:06.96 China Bingliang Li Guangzhou Wushan Open 2014
Average 00:10.21 China Bingliang Li Guangzhou Wushan Open 2014 00:09.36 / 00:11.43 / 00:06.96 / 00:09.83 / 00:12.06
Rubik's Clock Single 00:03.73 Sweden Nathaniel Berg Danish Open 2015
Average 00:05.94 United States Evan Liu Xi'an Cherry Blossom 2015 00:06.34 / 00:05.84 / 00:07.66 / 00:05.63 / 00:04.80
Skewb Single 00:01.10 Poland Jonatan Kłosko ŚLS Wodzisław Śląski 2015
Average 00:02.95 Poland Jonatan Kłosko Santa Claus Cube Race 2015 00:03.42 / 00:02.65 / 00:04.75 / 00:02.51 / 00:02.78
3×3×3: Blindfolded Single 00:21.05 China Kaijun Lin China Championship 2015
Average 00:25.45 Poland Marcin Kowalczyk Berlin Summer Cube Day 2015 00:25.88 / 00:29.22 / 00:21.24
4×4×4: Blindfolded Single 02:02.75 United Kingdom Oliver Frost Irish Championship 2015
5×5×5: Blindfolded Single 05:04.81 Russia Roman Strakhov MPEI Open 2015
3×3×3: Multiple Blindfolded Single 41/41 Poland Marcin Kowalczyk SLS Swierklany 2013 54:14
3×3×3: One-handed Single 00:06.88 Australia Feliks Zemdegs Canberra Autumn 2015
Average 00:10.87 Canada Antoine Cantin Toronto Spring 2015 00:10.56 / 00:14.19 / 00:10.58 / 00:10.07 / 00:11.47
3×3×3: With feet Single 00:20.57 Poland Jakub Kipa Radomsko Cube Theory 2015
Average 00:28.41 Brazil Gabriel Pereira Campanha SESC Santos 2015 00:29.72 / 00:26.97 / 00:28.53
3×3×3: Fewest moves Single 19 United States Tim Wong Irvine Fall 2015
Average 25.00 Germany Sébastien Auroux Velbert Easter Open 2014 27 / 27 / 21
United States Vincent Sheu US Nationals 2014 22 / 23 / 30
Germany Jan Bentlage CBNBC 2015 28 / 22 / 25
Germany Sébastien Auroux N8W8 Summer 2015 26 / 27 / 22
File:Progression of Rubik's Cube world records.jpg
A scatter plot of Rubik's Cube world records(single and average) against time. This depicts the improvement made over the years, as well as highlight records that stayed unbroken for an unusual amount of time.

[18]

Lubrication

Some members of the cubing community lubricate their cubes to allow them to be manipulated faster, easier, and more reliably than a non-lubricated cube. The WCA allows lubrication for official competitions.[19]

Some of the popular lubricants among speedcubers are:

  • Lubix Cube Lubricant
  • CRC Heavy Duty Silicone Spray
  • D-39 Silicone Spray
  • Cyclo Silicone Spray
  • Maru Lubricant
  • Traxxas 30/50K Differential Oil
  • Cubesmith Lubricant
  • Cubicle Silicone Lube/Lubicle

Checking a lubricant's MSDS is often helpful in identifying cube-damaging ingredients.

Building and Modification

A smaller portion of the cubing community, known as modders, dedicate themselves to creating ideas for new cubes, modifying existing cubes, and designing and producing the new puzzles themselves.

Building

The building of puzzles usually consists of start from scratch, from materials such as plastic sheets, or designing them in a 3D CAD software, such as programs like SolidWorks.

Modding

The modding community, larger than the aforementioned, takes existing puzzles and executes a process to have some desired effect. Most mods consist of simply sanding pieces down, to reduce friction, while other, more complex ones, involve cutting, shaping, and adding plastic to the puzzle to change shape and its overall mechanism and difficulty. These kinds of mods can range from simple ones such as the Cutter Cube, in which the center layer is misaligned, and the pieces are shaved down to make it seem as though it isn't, to more complex ones such as the Ghost Cube. It can be of any type.

Terminology

Below are some definitions of words generally used by the speedcubing community. For a more complete list of speedcubing terminology, see the cubefreak.net glossary.

Algorithm 
A predefined sequence of moves used to effect a specific change on the cube. Often referred to as alg or (less commonly) an algo.
BLD 
Blindfolded solving, i.e. memorize, don blindfold, then solve.
Center piece 
One of the centers of the faces of the cube. The centers never move relative to each other on an NxNxN cube, where N is odd. On NxNxN cubes where N>3, every piece with only one sticker is referred to as a 'center piece', including those pieces that can move relative to each other.
CLL 
Corners of the Last Layer. This is the first of two steps of one of the methods of solving the last layer of the cube. In the process, edges may 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). CLL is also commonly used to solve the last layer of a 2x2x2 cube in one step.
Commutator 
A commutator is a sequence of the form X.Y.X'.Y' (also represented as [X:Y] or [X,Y]) which affects only specific portions of the cube, leaving the rest untouched. This is used in Blindfolded solving and Fewest Moves Competition.
Corner piece 
One of the 8 pieces with exactly three stickers, called a "corner" piece because a corner is exposed.
Cuber 
Someone who solves any size of Rubik's Cube.
Cubie 
One of the mechanically independent pieces that make up a puzzle. The cubies do not include fixed center pieces, the central axis to which they are attached, or any other internal pieces (Such as the internal edges of a 4x4 or 2x2).
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 
Initialism for Did Not Finish, used in competitions and self-timing. e.g. when a piece pop occurs and the competitor decides not to continue solving the puzzle, or when the solver stops the timer with the cube still unsolved.
DNS 
Did Not Start, used in competition when the competitor does not begin a solve, either by opting to skip it (common in Blindfold Cubing), by not showing up when he or she is called, or not qualifying for the remaining (usually three) solves of a certain round.
Edge piece 
One of the 12 pieces with exactly two stickers, called an "edge" piece because only one edge is exposed.
ELL 
Edges of the Last Layer. The second of two steps of one of the methods of solving the last layer of the cube, solving the edge pieces without disturbing the corner pieces (see CLL).
F2B 
First two blocks. This is used in the Roux method.
F2L 
First two layers. This is used in the CFOP (Fridrich), Petrus, and ZZ methods.
GJ 
Short for Good Job, usually used to congratulate a cuber on a fast solve
Layer 
One section of a cube consisting of a number of cubies that turn as a unit. (e.g. A standard Rubik's Cube has 3 layers.)
LL 
Last Layer. Usually refers to the top layer of the cube, but for the Roux method can refer to the middle layer between the left and right faces.
Method 
A combination of steps that can be used to solve a cube.
Move 
A turn of one of the sides of a puzzle, or knobs in the case of the clock.
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'.
OH 
Short for One-Handed, it is the event or practice of solving a cube with one hand, left or right.
OLL 
Orientation of the Last Layer, usually used in reference to the respective step of the CFOP and ZZ methods.
Orient 
To change the orientation of a piece.
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 
To relocate certain pieces in a way to achieve a desired result.
Phasing 
Used in various methods, it is a technique that allows the shrinking of algorithm sets by using alternative moves. e.g. Using phasing with ZZ-a will turn it into a reduced subset known as ZZ-b.
PLL 
Permutation of the Last Layer. Usually used in reference to the respective step of the CFOP and ZZ methods, in which case it would follow the OLL step.
Pop 
When, during a solve, one or more cubies come out of contact with the puzzle, usually causing the puzzle to be unstable, in which, upon turning, more pieces may become loose.
Prime 
A counter-clockwise move popularly denoted with a ', e.g. 'R Prime', denoted as R', R-, R^{-1}, or Ri. Also (less commonly) known as "inverse" or "inverted".
Slice 
The four center pieces and four edge pieces between two opposite layers of the cube.
Two-Second Penalty, also known as +2 
A penalty of 2 seconds which is added to a solving time in official competitions when the cube is placed back on the timing pad with one or more faces misaligned 45 degrees or more. It can also be given in other cases, such as when the competitor starts the timer too slow or does not correctly stop the timer after finishing the solve.
UWR 
Unofficial World Record.
WCA 
World Cube Association, the international governing body for official cube competitions.
Winter Variation, also known as WV 
A subset of algorithms for F2L that allows the user to force all upper-face corners to be oriented correctly, or an OLL-Skip. It is used when the last F2L pair (One corner and its corresponding edge correctly positioned relative to each other) to be inserted is in the top layer, with the 3 top-layer edges oriented correctly. There are a total of 27 cases. WV has an average lower move-count than the standard OLL.
WR 
World Record. Can also be "World Rank" when referring to the rank of a person's record in a database.
X-Cross 
Completing an F2L pair during the cross setup, used almost exclusively in the CFOP method.
ZBLL 
Considered one of the holy grails of speedcubing. It is a set of 177 algorithms (Not including mirrors and inverses) with 494 cases to recognize in order to solve the last layer in one look, also known as 1LLL, with an average move count of ~12.08. Can be used in any layer-by-layer method that ends in N-Look LL, but will only really be efficient in ZZ, as the method keeps edges oriented, whereas methods such as CFOP do not keep the edges oriented, becoming a sometimes 2LLL solve.
YTUWR 
YouTube Unnofficial Word Record, the fastest of something that is posted on YouTube.

See also

References

  1. ↑ https://www.worldcubeassociation.org/regulations/#10h1
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  18. ↑ http://www.learnhowtosolvearubikscube.com/speedcubing-rubiks-cube/
  19. ↑ https://www.worldcubeassociation.org/regulations/wca-regulations-and-guidelines.pdf

External links

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