A robotic hand — which can beat any human challenger at rock, paper, scissors — has thrust Tokyo university into one of its biggest ethical dilemmas since the second world war: should Japanese academics lift a 70-year ban and exploit such technology to build weapons?

The debate within Tokyo University is set to resonate across Japan as an increasingly vocal general public unhappy at what it sees as Prime Minister Shinzo Abe’s attempts to rewrite the country’s constitution and unravel nearly 70 years of pacifism.

For some, the robot hand’s unerring ability to win a simple child’s game is an ingenious but harmless scientific breakthrough. Others envisage the technology being employed in anti-missile systems, armed battlefield droids and bullet-dodging drones.