Prime Minister Shinzo Abe's coalition and allies won two-thirds of the seats in parliament's upper house in Sunday's election.
The era of Japanese pacifism may be coming to an end after Prime Minister Shinzo Abe's Liberal Democratic Party (LDP) scored a super majority win in the upper house elections on Sunday.
The ruling LDP said the landslide victory was an indication that Japan was fully backing Abe's policies and the government promised to fix the fragile economy through a stimulus package.
But the two-thirds victory in parliament's upper house is being viewed by many in Japan as the moment the country may shift towards a more assertive military stance. LDP already has a two-thirds majority in the powerful lower house.
Japan's constitution has not been revised since it was drafted in 1946 and adopted in 1947 after the country's defeat in World War Two.
Under Article 9 of the constitution, Japan "forever renounced war and the threat or use of force as means of settling international disputes".
Japan, however, continued to grow significantly as a global military player all the while maintaining that its might was solely for defensive purposes.
That may now change.
"We have always set a goal of revising the constitution...that is my duty as president," Abe said after the results of the election trickled in.
"But the party does not have more than two-thirds of seats in both chambers by itself, so I don't expect the draft would pass as is," he said, also referring to the parliament's lower house and suggesting compromise was needed.
"So I hope debate will steadily deepen."
Abe's party won 56 of the 121 seats contested while the LDP's coalition partner, the Komeito party, grabbed 14 seats for a total of 70. It was a much better result than the Japanese premier had predicted.
The win and LDP's focus on constitutional reform, especially Article 9, was not so well received by China where the official news agency Xinhua termed the development "alarming".
"With Japan's pacifist constitution at serious stake and Abe's power expanding, it is alarming both for Japan's Asian neighbours, as well as for Japan itself," Xinhua said.
"Japan's militarisation will serve to benefit neither side."
Chinese Foreign Ministry spokesman Lu Kang said it was totally understandable that countries in Asia like China were concerned about Japan's "political direction".
Breaking the taboo on constitutional reform
Experts agreed that building agreement in Japan on amending the constitution for the first time would be tough.
Some in financial markets worry focus on the constitution will distract attention from the economy, but Abe promised to craft a large stimulus package.
"He must boost support to advance revision. So for constitutional change as well, he will probably come up with a large-scale economic package," said Daiji Aoki, senior economist at UBS Securities Japan.
Doubts about Abe's policies persist even though his ruling bloc won big in terms of seats. Many voters felt they had no other option, given memories of the main opposition Democratic Party's rocky 2009-2012 rule.
Surveys show many voters are wary of changing the constitution's war-renouncing Article 9, which advocates see as the source of Japan's post-war peace and democracy.
Conservatives see it as a symbol of humiliating defeat.
But convincing the Komeito party, the dovish junior partner in Abe's coalition, to agree would be challenging. The pro-revision camp might therefore tackle another amendment first.
One possibility would be to introduce a clause giving the government more powers in a national emergency, but critics say that would endanger civil rights.
Another option, floated by the Komeito, would be to add an environmental protection clause to the constitution. That less contentious step would nonetheless break the taboo on revision.
Revising the charter needs the approval of two-thirds in both houses of parliament and a majority in a referendum.
Economy the real problem
But a push to ease the constraints on the military policy will divert the government attention from reviving the economy, financial experts say.
"Markets want confirmation of Abe's strong grip on power, but they also want Abe to use that power for the economy first, not constitutional reform," said Jesper Koll, chief executive at fund manager WisdomTree Japan.
Abe has cast the election as a referendum on his "Abenomics" recipe of hyper-easy monetary policy, spending and reform.
With signs the strategy is failing, the government plans to compile a post-election stimulus package that could exceed 10 trillion yen ($99 billion).
But economists worry the government will choose big-ticket infrastructure projects rather than implement tough structural reforms.