The protest in front of the Prime Minister's Official Residence in Tokyo has been going on since March 29, 2012, according to one of the organizing groups.
It's on this Friday, June 22, same place, same time, whether it is being covered by the mass media or not.
From people at ".@TwitNoNukes":
Date: Friday, June 22, 2012
Time: from 6PM
Please refrain from carrying political signs not related to "anti-nuclear".
Prime Minister's Official Residence [東京都千代田区永田町２丁目３−１ 2-3-1 Nagata-cho, Chiyoda-ku, Tokyo, google map]
Kansai Electric Power Company headquarters [大阪市北区中之島3丁目6番16号 3-6-16 Nakanoshima, Kita-ku, Osaka City, google map]
Please follow the general guidance from the organizers.
According to their blog (rough translation by me; emphasis is mine),
We have been protesting against the restart of Ooi Nuclear Power Plant in front of the Prime Minister's Official Residence every week since March 29. Initially we had about 300 participants, but the number dramatically increased each week from 1,000 to 2,700, then 4,000, then 12,000. The Fukushima I Nuclear Power Plant accident is far from over, and yet the Noda administration has proceeded as if the restart was a given, without learning any lesson from the accident. The size of this protest continues to expand as anger toward the administration grows bigger.
The Noda administration has made the decision [to restart Ooi] ignoring the majority of citizens who are cautious about the restart. Therefore, we don't need to quietly accept their decision. From 6PM ono Friday June 22, we will protest against the restart of the nuclear plant in front of the PM's Official Residence. Also in Osaka, from 6PM to 7:30PM, we will protest in front of the KEPCO Headquarters. Let's show to the Noda administration that we demand the immediate retraction of the decision to restart Ooi Nuclear Power Plant and that we haven't given up at all, this time with the protest from 100,000 people or more, far exceeding 12,000 people last time. Please spread the information and please participate.
So it was 12,000, not 11,000 on June 15? Not sure if 100,000 people show up, but looking at the numbers of retweets on the posts announcing the weekly Friday protests, the interest at least to spread the word have increased in recent weeks.
Number of RT of the protests at .@TwitNoNukes blog:
For March 29: 2,283
For May 18: 4,447
For May 25: 2,627
For June 1: 5,856
For June 8: 5,741
For June 15: 8,612
For June 22: 10,005