The ruling Liberal Democratic Party (LDP), fresh from a landslide win in Sunday's Upper House election, is reported to be planning to start talks on revising Japan's post-war Constitution later this year.
Jiji news agency, citing LDP sources, said the party will "prioritise revisions that are more palatable to the public".
The LDP-aligned nationalistic political lobby, Nippon Kaigi, separately told a press conference yesterday that Japan urgently needs to "become a normal country" with more military powers, given recent geopolitical developments.
Nippon Kaigi chairman Tadae Takubo cited China's rejection of Tuesday's Arbitral Tribunal ruling against its claims to the South China Sea as proof of its expansionism.
"Japan is standing between an expansionistic China and a United States that might become more inward-looking," said Professor Emeritus Takubo, who specialises in international politics at Tokyo's Kyorin University.
These developments come three days after the Upper House election win gave Prime Minister Shinzo Abe's LDP and its allies control over both Houses of Parliament.
The LDP has already drafted a list of possible amendments, including the war-renouncing Article 9, that will give Japan's military more bite overseas. The revisions it will focus on for a start will likely include an "emergency situations clause" to allow the government to impose a state of emergency in events such as a natural disaster.
A debate will be called in an extraordinary parliamentary session this autumn, involving lawmakers of other political stripes in both chambers. This means lawmakers from the opposition Democratic Party and Japanese Communist Party, which strongly oppose constitutional revision, will be included.
Mr Abe, who aims to revise Article 9, is believed to be trying to get the public used first to the idea of revising the Constitution by pushing through less controversial clauses.
Any change to the Constitution, which has not been modified since it was enacted in 1947, must be backed by at least two-thirds of lawmakers in both Houses - which the LDP and its allies now have.
It must also win a simple majority vote in a national referendum that has to be called within six months of the legislature's proposal.
Amending the Constitution has been the LDP's goal since it was formed in 1955, and Mr Abe said on Monday: "To realise the revision of the Constitution is my duty as LDP president. But it is not that easy, so I hope debate will deepen steadily."
Prof Takubo of the Nippon Kaigi, which has 38,000 members, yesterday noted that the level of control the LDP has in the Parliament is unprecedented.
As such, it presents Mr Abe with the "perfect chance, and the very first opportunity we've had" to amend the Constitution.
Nearly 40 per cent of the lawmakers in the Diet - including Mr Abe and most of his Cabinet ministers - are affiliated with the group.
Prof Takubo said Mr Abe's approach has been to shift Japan from the "extreme left towards the centre" - and not from the "centre to the extreme right".
"If I were in Mr Abe's position, I would be putting forward all my efforts during my tenure as Prime Minister to achieve the amendment," he added.