With the ruling Liberal Democratic Party's long-held plan to revise the pacifist Constitution becoming increasingly concrete and real, both backers and opponents of the supreme law marked its 68th anniversary Sunday with rallies to drum up support for their causes.

There was a growing sense of immediacy in both camps, as the LDP is aiming to have the Diet initiate the process for amending the U.S.-drafted Constitution in 2017, following the Upper House election in summer 2016, and then hold a referendum.

Around 30,000 people gathered at Rinko Park in Yokohama to argue against what they see as Prime Minister Shinzo Abe's efforts to steer the nation toward war.

In an event organized by the liberal activist group Antiwar Committee of 1000, participants held up banners and signs that read "No War" and "Protect Article 9," while prominent writers and activists appeared on stage and criticized the Abe administration's plans to revise the Constitution.

Nobel-winning author Kenzaburo Oe expressed concern that, under Abe, Japan is marching toward a third world war.

Despite Abe's speech before Congress in Washington last Wednesday, in which he trumpeted Japan's peacekeeping policies, he hasn't explained enough to his own people about his "pro-war" policies — including the Cabinet's decision to reinterpret the Constitution, rather than amend it, so the nation can exercise the right to collective self-defense, or coming to the aid of an ally under armed attack, Oe said.

"What I want to say out loud is we have to reject Abe's policies such as collective self-defense and 'proactive pacifism,' which are just self-justification for getting involved in a future war," he said.

Another speaker, activist and author Karin Amamiya, blamed Abe for increasing poverty among youths, arguing that young people will be the first to be sent to the battlefield if a war ever breaks out.

“The number of working poor has grown under the Abe administration,” she said. “Those who are currently pushing for the security legislation will never go to war. It is the massive ranks of the poor people who will.”

Proponents of revision meanwhile held an event near Tokyo’s Nagata-cho district.

Organized by a group of conservative intellectuals named Utsukushii Nippon no Kenpo wo Tsukuru Kokumin no Kai (Citizens' Group to Create a Beautiful Japanese Constitution), the event, attended by about 900 people, sought to call people's attention to the "urgent" need to bring the Constitution up to date.

Even as security environments around the globe are rapidly changing — what with China's growing military assertiveness in the South China Sea and terrorist threats posed by the Islamic State religious extremists in the Middle East — Japan remains "fettered" by war-renouncing Article 9, organizers said.

"We need to do, under the Abe administration, whatever it takes to protect Japan. Thus it's high time to rewrite the Constitution, which lays the very foundation of our nation," said Yoshiko Sakurai, a conservative journalist who co-heads the group, adding the revised version should grant the Self-Defense Forces full-fledged military capabilities to help Japan better coordinate with other nations in curbing China's "menacing" rise.

Yosuke Isozaki, secretary-general of the LDP's group pushing for constitutional amendments, said the next Upper House election in summer 2016 will be crucial, noting that the goal is to get as many pro-amendment politicians as possible elected in the race.

A constitutional amendment requires a two-thirds approval from both chambers of the Diet before it’s put to a national referendum. Although the ruling coalition of the LDP and Komeito occupy two-thirds of the Lower House, pro-amendment forces do not have a two-thirds majority in the Upper House.

In a 64-page educational manga booklet unveiled by the party last week, the LDP portrayed the pacifist Constitution, drafted by the Allied Powers, as designed to “incapacitate” Japan so that “it would never become a threat to the global society.”