On a rainy midwinter day, Taro Yamamoto stood with a small group of people in front of Shimokitazawa Station in Tokyo's Setagaya Ward and addressed passers-by in that artsy youth-culture hub.

"I am an actor — Taro Yamamoto," he announced. "And I would like to ask you to add your signature to a petition we are putting together that calls for a local vote on nuclear power plants."

The 37-year-old went on to explain that the campaign aims to get the signatures of 214,236 of Tokyo's eligible voters (one 50th of the total). Members of the Tokyo Metropolitan Government Assembly would then be legally bound to vote on whether to hold a referendum among the citizens within its jurisdiction, asking if Tokyo Electric Power Co. — operator of the crippled Fukushima No. 1 nuclear power plant — should be allowed to run such facilities or not.