In its editorial on Feb 5, the paper says that United States Defence Secretary James Mattis's assurance that Washington will adhere to to its defence treaty with Tokyo marks an important first step for reinforcing the alliance between the two nations.
The latest development should be regarded as one that has marked an important step between Japan and the new United States administration under President Donald Trump for reinforcing the Japan-US alliance.
US Defence Secretary James Mattis came to Japan and held talks with Prime Minister Shinzo Abe, Defence Minister Tomomi Inada and other Cabinet members. Mr Abe welcomed Mr Mattis' visiting Japan so soon after taking office and said: "I want to have the unshakable alliance further solidified."
Mr Mattis made it clear that Article 5 of the Japan-US Security Treaty, which stipulates US defence obligations for Japanese territories, would be applied to the Senkaku Islands in Okinawa Prefecture. He also said the US opposes any unilateral action that would undermine Japan's administrative control.
China is intensifying the actions of its military aircraft and warships in the East China Sea, while having its government vessels constantly enter Japan's territorial waters around the Senkaku Islands. Mr Mattis' opinion will strongly keep China in check.
It is important for the Self-Defence Forces and US forces to cooperate more closely than ever and deter China from undertaking its self-serving maritime expansion.
With regard to China's militarisation of artificial islands it has built in the South China Sea, Mr Mattis criticised China's actions, saying that China "has shredded the trust of nations in the region". Japan and the US, in cooperation with South-east Asian countries, should prevail upon China to exercise self-restraint.
Concerning a future Japan-US alliance, Mr Abe emphatically said: "Japan will strengthen its defence capabilities and expand the roles it can play."
Mr Mattis, for his part, urged that "we must not be found complacent... It will be important for both of our nations to continue investing in our defence capabilities".
The Japan-US alliance is a public asset that underpins the peace and prosperity of the Asia-Pacific region. Amid the increasing factors of uncertainty, such as China rapidly building up its military and North Korea developing its nuclear and missile programmes, Japan will be put to the test as to what roles it can assume.
Including an increase in its defence budget, which remains only at 1 per cent of the nation's gross domestic product, Japan should move ahead with what it can do.
It is important to expand joint drills and surveillance activities with countries concerned, including the US. Discussions should also begin in earnest concerning the study of the possibility of Japan's acquiring the ability to strike enemy bases before a missile attack is initiated, which Mr Abe referred to during a Diet session last month.
The issue about the way Japan's cost-sharing for US forces stationed in Japan should be was not taken up for discussion during the series of talks. But at a press conference, Mr Mattis appraised the situation. "We can point to our Japanese-American cost-sharing approach as an example for other nations to follow," he said.
His remarks are considered as Mr Mattis taking into account Japan's cost-sharing totaling as much as about 761.2 billion yen (S$9.5 billion) a year - the largest amount among US allies - including expenses for US forces' reorganisation. It is an appropriate understanding.
During his presidential election campaign, President Trump said that he would seek large increases in the costs shouldered by Japan for US troops stationed in Japan. Mr Abe needs to explain again Japan's cost-sharing in detail when he meets Mr Trump on Feb 10.
With regard to the planned relocation of the US Marine Corps' Futenma Air Station in Ginowan, Okinawa Prefecture, Mr Abe and MR Mattis shared the view that the current plan to relocate it to the Henoko district in Nago in the same prefecture is "the only solution". Work related to the relocation, which has been delayed due to the opposition of the Okinawa prefectural government, needs to progress steadily.
The Yomiuri Shimbun is a member of The Straits Times media partner Asia News Network, an alliance of 22 news media entities.