TOKYO - "Firmly oppose arbitrary revision of the Constitution!" "No to war!" "Safeguard the pacifist Constitution!" On Sunday, around 50,000 people gathered at Tokyo Rinkai Disaster Prevention Park, chanting slogans and holding banners against the government's push for constitutional revision and military expansion, the largest turnout in recent years.

Sunday marks Japan's Constitution Memorial Day, commemorating the day the country's current Constitution took effect in 1947.

Widely known as the pacifist Constitution, the supreme law's Article 9 renounces war as a sovereign right of the nation and the threat or use of force as a means of settling international disputes. It also stipulates that Japan will never maintain land, sea, and air forces or other war potential, and that the right of belligerency of the state will not be recognized.

At this year's rally, held as Prime Minister Sanae Takaichi accelerates efforts to revise the Constitution, public unease was more visible than ever.

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Tomoko Tamura, chair of the Japanese Communist Party, said in her speech that the Takaichi administration's push to revise the Constitution and attempts to add the Self-Defense Forces (SDF) into it could fundamentally weaken restrictions on overseas dispatches of SDF.

"The Constitution is a constraint imposed by the people to prevent the state from waging war again," she said. "Yet the authorities are now stoking crises and promoting military expansion, which is absolutely unacceptable."

Mizuho Fukushima, leader of Japan's Social Democratic Party, also pointed out that the Takaichi administration is "hollowing out the pacifist Constitution bit by bit."

Noting that the government has already relaxed restrictions on arms exports by cabinet decisions alone, even allowing the export of lethal weapons, while the bill to establish a new national intelligence committee has cleared the House of Representatives, she said: "This is a path to war."

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The atmosphere on the stage was somber, while the mass crowd below held up placards calling for the protection of the Constitution and at times chanted along with the speakers.

Many parents attended with their children. The younger ones, perhaps too young to grasp what a constitution even means, ran about laughing and playing in small groups, while the worry on their parents' faces was hard to miss.

A participant identified as Kagawa, who attended the rally with his three children, told reporters that he found it hard to accept that Takaichi, who had not made such sweeping security policy changes a central part of her campaign during the Liberal Democratic Party (LDP) leadership race or the general election, is now pushing the agenda forward at such a rapid pace.

"These security policies are decided by adults, but it is the children of today who will bear the consequences. They will grow up in an increasingly tense international environment. This is something we adults must think about seriously," he said.

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With 81 years having passed since the end of World War II, Kagawa warned that the collective memory of the war is fading. "Under such circumstances, society may be more prone to drift toward constitutional revision, and that is something I am deeply wary of."

Kagawa also expressed concern about what he described as "patriotic education" in Japanese schools. He warned that if such education places too much emphasis on "what must be defended in the name of patriotism," it risks leading students to the misguided view that war, or even the possession of nuclear weapons, is an unavoidable choice. "That also deeply worries me," he added.

Yoneyama, a mother who attended the rally with her nine-year-old child, told reporters that Japan has adhered to the current Constitution for nearly 80 years, yet the government is now in such a rush to revise it.

"I can't help but wonder whether they are trying to build a society more prone to waging war," she said. Glancing at her little one, she added, "I absolutely do not want him to go to war someday. I just want Japan to remain a peaceful nation forever."

On the same day, however, a pro-revision rally was held elsewhere in Tokyo. The dominant message there was that "Japan is facing the most severe and complex security environment since the end of WWII, and urgently needs to revise Article 9."

In a video message to the gathering, Takaichi said that the Constitution "should be periodically updated in accordance with the demands of the times."

Just weeks ago, at an LDP convention on April 12, she declared that "an independent constitutional amendment by the hands of the Japanese people is our party's long-cherished goal" and that "the time has come.

Masakatsu Adachi, emeritus professor at Japan's Kanto Gakuin University, warned that politicians must place Article 9 at the very core of any discussion on security policy.

"If Japan assesses the global situation without grounding itself in Article 9, it could gradually slide back to its prewar state," he cautioned.