Thousands of people packed Nippon Budokan Hall in Tokyo on Tuesday in support of revising the pacifist Constitution while pledging to collect 10 million signatures favoring their cause.

The organizing group claimed 11,321 people attended the political rally at one of Japan’s most prestigious halls, located in Chiyoda Ward.

The group, Utsukushii Nippon no Kempo wo Tsukuru Kokumin no Kai, (National Society to Create a Constitution for a Beautiful Japan), said it has already gathered signatures from 4.45 million people, including 422 Diet members, expressing their support for constitutional revisions of one kind or another.

Prime Minister Shinzo Abe, who also serves as president of the ruling Liberal Democratic Party, sent a congratulatory video message to the rally.

“The Constitution has never been revised. I think the time has come to seek a Constitution suitable for the 21st century,” Abe said in the recorded speech played for the crowd.

He also pointed out that any revision would require support of more than half of the voters in a national referendum, urging the group to promote campaigns to first “form a national consensus” on constitutional revision.

So far, national opinion polls have suggested less than half of voters support any revision of war-renouncing Article 9.

As a result, Abe has pledged to prioritize economic issues, not constitutional revision, at least until the Upper House election next summer.

“Let’s proceed together in steady steps toward revision of the Constitution,” Abe said in the video message.

To initiate a national referendum on constitutional revisions, support from at least two-thirds of the lawmakers in each of the 475-seat Lower House and 242-seat Upper House is required. This equates to at least 317 Lower House members and at least 162 Upper House members.

The group didn’t give a breakdown of the 422 Diet members who it said support some form of constitutional revision.

The signature form put forward by the group doesn’t specify which article of the Constitution should be revised. This could be a device to garner support from as many voters and Diet members as possible, regardless of which parts of the Constitution they would like to amend.

The National Society to Create a Constitution for a Beautiful Japan is considered a group derived from the Japan Conference (Nippon Kaigi), the nation’s largest nationalistic citizens’ group.

The two groups share most of their key members, including Tadae Takubo, the head of the Japan Conference, and journalist Yoshiko Sakurai.