The 20-Move Rubik’s Cube Challenge Unveiled

Serious Rubik’s Cube solvers always employ some kind of algorithm, or set of steps, to get the job done. Algorithms range from very simple to very complicated, with the number of moves needed to memorize and apply them generally exceeding forty. However, in terms of really employing the most efficient solution for a particular position on a regular Rubik’s Cube, this value may seem a bit high. Tomas Rokicki, Herbert Kociemba, Morley Davidson, and John Dethridge demonstrated in July of 2010, with the help of 35 CPU years* of computer time supplied by Google, that solving any position on a normal Rubik’s Cube requires no more than 20 movements.

Notably, not every position was solved using the optimal approach by the researchers. On the contrary, they abandoned efforts to find optimal solutions for the other locations once they realized that solving one would undoubtedly require 20 moves. Solving it in 20 moves or less was all that was needed to ensure it was below the now-known upper bound. They reasoned that this quantity must be the maximum number of movements required to solve any position on a regular Rubik’s Cube, provided that all other positions could be achieved in less time. The main advantage of this approach was the significant reduction in computations needed to demonstrate that no ordinary Rubik’s Cube position required more than 20 moves to solve.

The amount of work that one Giga-FLOP computer is capable of completing in a year is sometimes referred to as a CPU Year. FLOP stands for Fluctuating Point Operations Per Second. To put it simply, one FLOP machine can perform a single operation every second, while a Giga-FLOP machine can execute one billion operations per second. Interestingly, there are fewer possible Rubik’s Cube configurations than the number of operations necessary to prove the above—35 CPU years, or approximately 1,103,760,000,000,000,000—operations. To delve deeper into the specifics of how they achieved this remarkable feat with relatively few procedures, read on.

Each of the 26 cubes in a regular Rubik’s Cube includes an inside extension that locks into place with every other cube. These internal mechanisms are supported by the core mechanism, which is locked to the center cube of each of the six sides of the cube.

Taking a Rubik’s Cube apart and rearranging the pieces in a way that solves it when put back together is the simplest way to solve it. Alternatively, you can move the stickers around, but doing so runs the risk of ripping them and exposing your cheating.

In 1974, Ernő Rubik, an architect and lecturer from Hungary, inadvertently created the Rubik’s Cube while exploring the structural problem of keeping the cube intact while moving its blocks independently for an infinite number of rotations. Initially, he didn’t intend to make a puzzle out of it; his focus was primarily on finding a solution to the structural challenge. His magic cube was first commercialized shortly after its conception in 1975 when he applied for and was awarded the Hungarian patent HU170062.

In 1980, Rubik granted Ideal Toy Corp. a license to sell the puzzle. Due to Rubik’s failure to meet the deadline for filing an international patent, anyone could make and sell these magic cubes outside of Hungary. Instead of continuing with the generic Magic Cube brand, Ideal Toy Corp decided to go with the more memorable and trademarkable Rubik’s Cube. This decision helped them overcome this challenge to some extent. Rubik eventually received patents for the Rubik’s Cube from several nations, including the US in 1983.

Terutoshi Ishigi, a self-taught engineer from Japan, independently came up with the Rubik’s cube in 1976. Since he invented his cube at roughly the same time as Rubik’s, it was virtually identical to Rubik’s cube both on the inside and out—though he had no idea of this. However, since Ishigi didn’t obtain his patent (in Japan) until roughly a year after Rubik in Hungary, the credit for his invention goes to Rubik.

In January 2009, worldwide sales of Rubik’s Cubes reached an impressive 350 million units, showcasing the enduring popularity of this iconic puzzle. The goal of speedcubing is to find the solution to a Rubik’s Cube as quickly as possible. On March 13, 1981, Munich hosted the inaugural Guinness World Championship, marking the beginning of competitive speed skating.

Feliks Zemdegs set the current world record for a 3×3×3 Rubik’s Cube at the 2011 Melbourne Winter Open with a remarkable best time of 5.66 seconds. Did you know that it would take 1,400,000,000 years to go through all the potential configurations of a Rubik’s Cube if you turned the face of the cube every second? It’s a testament to the puzzle’s complexity.

A Puzzling Divorce

In an unusual twist, the Rubik’s Cube was named as a co-respondent in a 1981 divorce suit filed by Frau Schmit of Dusseldorf, Germany, against her husband. Her statement read: “Gunder no longer speaks to me, and when he comes to bed, he is too exhausted from playing with his cube to even give me a cuddle.”

A Cube Fit for Royalty

Diamond Cutters International’s 1995 “Master Cube” takes the title of the priciest Rubik’s Cube ever built. This completely functional cube, of standard size, boasts an astounding 22.5 carats of amethyst, 34 carats of rubies, and 34 carats of emeralds set in 18-carat gold, with an estimated value of approximately 1.5 million dollars.

Tips for Mastering the Rubik’s Cube

Get to Know Your Cube

Before diving into solving the Rubik’s Cube, familiarize yourself with it. Understand the structure, the six faces, and how the colors are arranged. Knowing your cube inside out will be your foundation for success.

Choose a Solving Method

There are various solving methods for the Rubik’s Cube, such as the CFOP method and the beginner’s method. Pick the one that suits your skill level and commitment. The beginner’s method is an excellent starting point for newcomers.

Practice, Practice, Practice

Solving the Rubik’s Cube is all about muscle memory. The more you practice, the better you’ll get. Dedicate time each day to solving the cube, and you’ll notice improvement over time.

Start with One Layer

When you’re just beginning, focus on solving one layer of the cube first. This will help you build confidence and understand the basic moves required for each face.

Understand Notation

Familiarize yourself with cube notation, which uses letters to represent different moves. Learning this notation will help you follow algorithms and solve the cube more efficiently.

Learn Algorithms

To solve the Rubik’s Cube, you’ll need to memorize a set of algorithms. These are sequences of moves that will help you manipulate the cube to achieve specific patterns. Practice these algorithms until you can execute them smoothly.

Keep Your Cool

Solving the Rubik’s Cube can be frustrating at times, especially when you make mistakes. Stay patient and composed. Remember that practice makes perfect.

Experiment with Different Patterns

Once you’ve mastered the basics, experiment with creating different patterns on the cube. This will deepen your understanding of how it works and make solving more enjoyable.

Challenge Yourself

As you become more proficient, challenge yourself with timed solutions. Set personal records and try to beat them. This will push you to improve your speed and accuracy.

Join a Rubik’s Cube Community

There are online communities and forums dedicated to Rubik’s Cube enthusiasts. Join one to share your progress, learn new techniques, and connect with fellow cubers.

Maintain Your Cube

A well-maintained cube is easier to solve. Clean and lubricate your cube regularly to ensure smooth movements.

Stay Informed

Stay updated with the latest developments in the world of Rubik’s Cube solving. New techniques and records are constantly emerging, so keep an eye on the community’s achievements.

Have Fun

Remember that solving the Rubik’s Cube is not just about speed and algorithms; it’s about having fun. Enjoy the challenge, embrace the learning process, and celebrate your successes, no matter how small they may seem.

Share Your Passion

If you become passionate about solving the Rubik’s Cube, share your knowledge and enthusiasm with others. Teach friends or family members how to solve it and spread the joy of cubing.

Explore Other Puzzle Variations

Once you’ve conquered the standard Rubik’s Cube, consider exploring other puzzle variations like the 4×4 or 5×5 cubes. Each offers a unique challenge and a chance to expand your cubing skills.

The Rubik’s Cube is not merely a puzzle but a symbol of creativity, ingenuity, and endless possibilities. Its rich history, intriguing design, and global appeal continue to captivate minds and inspire enthusiasts around the world. Whether you’re a speedcuber aiming to break records or a casual solver seeking a moment of mental challenge, the Rubik’s Cube has something to offer everyone.