A Robot Has a 100% Win Rate at Rock-Paper-Scissors

Rock-paper-scissors has always been one of those games that you play with the notion in mind that the victor is the luckier of the two. A long-time settler of disputes, rock-paper-scissors has been the deciding factor in many impasses where two (or more) individuals felt a resolution could only be determined by the gods of luck. Unfortunately, modern technology has shattered these notions as a robot created in Tokyo’s Ishikawa Oku Laboratory boasts a 100% victory rate against humans in rock-paper-scissors.

The robot’s name is Janken.

How Does it Work?

The robotic hand would appear on the surface to be simply playing off intuition, but there is actually a high-speed camera that detects the human hand’s shape within one millisecond (0.001 seconds) and triggers a response from a high-speed robotic hand that beats whatever the human throws down.

According to the Ishikawa Oku Laboratory’s website, “Recognition of [the] human hand can be performed at one millisecond with high-speed vision, and the position and the shape of the human hand are recognized.” That’s pretty fast visual recognition, and acting on this recognition is something humans do a bit slower. It isn’t until the footage is slowed down considerably that you’d notice the robotic hand is actually playing after the human. At a glance, it appears to be acting in sync.

Potential Uses for the Technology

Aside from the parlor trick of having a robotic hand that wins at rock-paper-scissors, the long-term implications of robotics that can respond to human motion and gestures is very significant.

The Ishikawa Oku Laboratory site states, “This technology is one example that show[s] a possibility of cooperation control within a few milliseconds. And this technology can be applied to motion support of human beings and cooperation work between human beings and robots, etc. without time delay.”

This means anything from prosthetics to assistive motion devices could feasibly benefit from this real-time robotic response technology. Injured veterans and disabled individuals may benefit from this technology as it makes it easier to adapt to life’s challenges.


While a lightning fast robotic arm that responds to hand positions in milliseconds looks impressive on video, the technology has not been developed to do much beyond these simple tests. We’re not months away from the T-100 taking out rebels in a trench while shouting, “I’ll be back.”

What the video shows is a proof of concept that demonstrates what is possible when you combine visual recognition software, fast processing technology, high-speed cameras, and a quick robotic element together.

While the technology behind this proof of concept is fantastic, the innovations that develop from it will no-doubt be more interesting than a robot that wins at rock-paper-scissors. The programming is very simple at this point, so any advanced interactions such as shaking hands and dealing cards in response to a Blackjack player’s hand signals is still some time away.

Other Impressive Robotic Projects

Roborazzi is a design concept invented by the robotics division of Microsoft to demonstrate the abilities of the Microsoft Robotics Studio. It rolls around a given space with a camera. As it comes across someone’s profile, it recognizes their frame and tells them to say cheese before snapping a photo.

The concept behind Roborazzi is that of the ultimate party photographer. It rolls randomly (or controlled) around the room, avoiding obstacles, and taking shots of folks in attendance in a way that would be difficult for a human photographer. After all, who wants to give up their party time to take all those snapshots?

During last year’s Gnomedex conference, Roborazzi was the highlight of the presentation as it zipped around the audience, taking pictures of attendees.


The BlueBiped robot is essentially a set of robotic legs that can continue, practically self-propelled, for quite a while. The trick is in how the BlueBiped utilizes gravity as a motivating force. In concept, it could provide assistive support for disabled individuals who find it difficult to walk for extended periods of time under their own power.

One of the current limitations of the system is that it works best by going downhill. Uphill climbs take the potential energy element out of the equation and make long distances difficult. It does, however, open the door to low-energy prosthetics and athletic equipment in the future.

A Robot Has a 100% Win Rate at Rock-Paper-Scissors

Final Thoughts

It’s hard to imagine just how far robotics have come in the past decade, or where they might be going in the next 10 years. Artificial intelligence is improving, and the speed of various robotic functions is also on the rise. Combining functional elements such as robotic joints and actuators with modern software and advanced processors paves the way for science fiction to become reality.

Don’t worry though, we’re still quite a long way from Skynet and the eventual collapse of mankind. Artificial intelligence has come a long way, but even the most advanced software has severe learning limitations. For now, we can enjoy the creature comforts of smarter robotics and the many advantages these technologies being developed today have for assistive technologies. Perhaps in another 10 years, we’ll be doing a lot more than losing to simple games of rock-paper-scissors. It’s only a matter of time before these machines start beating us at more advanced games, like rock-paper-scissors-lizard-Spock.

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