A robot that wins rock-paper-scissors every time!

By Casey Frye, CCNN Writer

rock paper robot
Humans have no chance of winning.

It may be simple, but rock-paper-scissors is probably one of the most important battles on the face of the planet. People all over the world use it to settle bets against their buddies, determine chore work with their siblings, and even demonstrate quick thinking skills… or sheer luck. Whatever your purpose is, don’t go battle against University of Tokyo’s Janken robot, because it’s designed to win every time!

Unlike humans, who have to predict what hand shape their opponent is going to throw out, the Janken robot relies on high-speed recognition and reaction. It’s so fast, in fact, that the robot can tell what shape our hand will make as it’s forming either a rock, paper, or scissors in mid-air, reacting within milliseconds. You’ve probably done the same thing with your buddies a couple of times. You know, that one friend who moves his hand so slow, you can tell what he’s going to throw down and respond accordingly? Yeah, that’s what the Janken robot does, only much, much quicker.

It’s even speedier than the first version of this robot, which took just 20 milliseconds to react. The new model only needs 1 millisecond to make its winning choice! However, the researchers are still unsatisfied with that speed. Sethu Vijayakumar, professor of robotics at Edinburgh University, explains: “These robots are really fast at reaction, but there are scenarios where even a millisecond’s delay is not acceptable, such as accident avoidance or virtual stock markets.” Ah, so this is not just about silly games.

But still, what can be better than 1 millisecond? Deciding simultaneously! If the robot designers can get the Janken robot up to that instant level of recognition, it can be included in a whole bunch of technologies such as “sensor fusion,” which uses high speed intelligent robots to copy and improve the human senses.

Images courtesy of Ishikawa Oku Laboratory.