A Rubik’s Cube or puzzle cube has 43,252,003,274,489,856,856,000 possible combinations, yet there are people in this world who can solve any of them in a matter of seconds.
Known as ‘speedcubers’, they have competed against each other for years in order to achieve the world record for the fastest time to solve a rotating puzzle cube.
The first official record holder was Minh Thai, a Vietnamese refugee who won the inaugural World Rubik’s Cube Championship in 1982 with a time of 22.95 seconds.
40 years on, the record time is now just 3.47 seconds, achieved by Yusheng Du (China).
But just how fast can the record get?
In order to answer this question, let's take a brief look at the history of this ultra-competitive and globally revered record.
After the 1982 World Championship, interest in speedcubing waned and it took over 20 years for the next competition to take place.
At the 2003 World Rubik's Games Championship, which celebrated the 25th anniversary of the Rubik's Cube, the world record was broken twice. First by Dan Knights (USA) in 16.71 seconds, followed by Jesse Bond (Denmark) with 16.53 seconds.
The scene was then dominated by Shotaro Makisumi (Japan), who broke the record four times between 2003-04. Registering a time of 12.11 seconds in October 2004, he single-handedly shaved over four seconds off the world record in under a year.
As impressive as this was, competition remained fierce and the record was broken repeatedly over the next few years:
2006 - 11.13 seconds, by Leyan Lo (USA)
2007 - 9.55 seconds, by Ron van Bruchem (Netherlands)
2008 - 7.08 seconds, by Erik Akkersdijk (Netherlands)
Nobody was able to beat Erik’s record for a relatively long time after that. It remained unbroken for two years and four months, until November 2010 when 14-year-old Feliks Zemdegs (Australia) entered the scene.
Feliks broke the 7-second barrier with a time of 6.77, but he wasn’t planning on stopping there. Over the course of 2011, Feliks broke his record several times, lowering it to 6.24 seconds.
Two years later, Mats Valk (Netherlands) finally broke Feliks’ record with a time of 5.55 seconds. Two years after this, Collin Burns (USA) set a new record at 5.25 seconds.
As the time to beat got marginally lower and lower, the record was being broken less frequently. However, that all changed on 21 November 2015.
At River Hill Fall 2015, Collin Burns wowed attendees with a 5.21-second solve, but the world record was soon snatched away from him by Keaton Ellis (USA) who registered a time of 5.09 seconds. Amazingly, in the next round of the competition, Lucas Etter (USA) then became the first person to solve a cube in under 5 seconds, with a time of 4.90.
Lucas used a method invented by Jessica Fridrich, who predicted that the fastest time her method could ever achieve was 13 seconds. The abilities of human speedcubers had now progressed even beyond the imagination of pioneers such as Jessica.
Feliks Zemdegs reclaimed the record in 2016, before losing it in 2017 and then winning it back once more in 2018 with a time of 4.22 seconds.
Had the limits to human capability been reached?
Six months later, this question was answered
At the Wuhu Open 2018, a relatively-unknown speedcuber by the name of Yusheng Du smashed Feliks’ record, with a time of 3.47 seconds. This is the current official record for the fastest time to solve a rotating puzzle cube.
Du’s achievement was so unexpected that he wasn’t even being filmed at the time. Luckily, his attempt was caught by a security camera and WCA delegates were on-hand to confirm the legitimacy of the scramble and the solve.
So, can this record be broken?
Amazingly, it’s already been done, albeit unofficially.
As seen in the below video, 12-year-old Ruihang Xu has solved a cube in 2.68 seconds, a time previously thought impossible to achieve.
However, this cannot be registered as the official world record because it was not performed in a World Cube Association (WCA) competition. All speedcubing records are ratified by the WCA, whereupon they are also recognized by Guinness World Records.
14-year-old Leo Borromeo has also solved a cube on camera in 2.78 seconds. When WCA events fully resume post-COVID, an official sub-3-second time is expected to be set by one of the sport’s many rising stars.
What limits a speedcuber’s speed?
In the decades since Ernö Rubik’s first iteration of the cube, it has been upgraded in many ways. The original cube was clunky, stiff and awkward to rotate, whereas newer models can be easily turned and contain magnets to help the faces snap into position.
“If you give me a cube from five years ago, it’s probably taking like a second off my solve time,” Feliks Zemdegs told WIRED in 2019.
Additionally, there are many methods to solving the cube. They are all reliant on the memorization of ‘algorithms’, which are sequences of moves used to solve the cube section by section. The more algorithms you know, the fewer moves you will require to solve a cube.
Memorizing hundreds of algorithms can only take you so far though; they are useless if your fingers can’t keep up with your brain.
The world’s fastest speedcubers can perform around 10-12 turns per second during the course of a solve. This requires extremely fast fingers, but ultimately there is a limit to the speed at which humans can move. Eventually, we will reach a speedcubing barrier that cannot be broken by any human.
So how fast can a machine do it?
The fastest robot to solve a puzzle cube was built by MIT students Ben Katz and Jared Di Carlo in 2018. It solved the cube in just 0.38 seconds.
There are two advantages this machine has in comparison to humans.
Firstly, it has a huge speed advantage. The robot turns the cube at a speed of around 55 turns per second – five times faster than a human.
Secondly, the machine is highly accurate. It neatly aligns all faces of the cube after each turn, which means there are no 'cut corners'. The technique of corner cutting is used by speedcubers to save time as it allows a half-turned face of the cube to be pushed into place by moving another face.
However, at high speeds this could cause the cube to break apart. So if a human was somehow able to match the speed of a machine, they would also need to match its accuracy.
Therefore, whilst we don’t yet know the limit to how fast a human can solve a Rubik’s Cube, we can say with some confidence that it’s somewhere between the 0.38 seconds achieved by MIT and the 2.68 seconds achieved (unofficially) by Ruihang Xu.
As speedcubers around the world continue to hone their skills and battle for the world record, we are cautiously optimistic that a sub-2-second solve – thought to be impossible by many – will be achieved one day.
Comments
Post a Comment