When Japanese Foreign Minister Nobutaka Machimura asked Israel to halt weapons sales to Japan's neighbors on the weekend, there was little doubt which particular neighbor he had in mind.
And when Japan's defense ministry recently drew up contingency plans to deploy 55,000 troops in the event of an invasion of disputed islands off southern Japan, there was no question who the most likely invader would be.
While the world watches China's rapid rise towards superpower status with awe, Japan, China's old enemy, watches with foreboding.
It is almost inconceivable that Japan and China would ever fight again. The two countries are increasingly economically interdependent. But relations are certainly deteriorating.
Political tensions, territorial rivalries, competition over energy resources and China's military build-up -- dramatized by a recent, illegal incursion by a nuclear submarine -- provide the ingredients for a 21st-century oriental remake of the Cold War.
Japan's brutal 1930s wars of conquest are far from forgotten or forgiven in China.
But anti-Japanese nationalist sentiment is now being exploited to boost the Communist Party leadership's waning ideological authority.
Chinese anger focuses on the visits of Japanese Prime Minister Junichiro Koizumi to Tokyo's Yasukuni shrine, where war criminals are commemorated alongside Japan's war dead. China says this proves Japan has not truly repented its militarist past.
Beijing refuses to hold bilateral summits until Koizumi kowtows, and for this reason, among others, is opposing Japan's bid for a UN Security Council seat. The antipathy is mutual.
A survey last year found that 58 percent of Japanese -- like most Taiwanese -- fear China's long-term intentions.
For the first time, Japan's latest defense review named China, along with North Korea, as a potential threat.
Meanwhile, Koizumi has suggested ending economic aid, which Beijing regards as its right in lieu of war reparations.
As Machimura made clear, Japan wants all countries, not just Israel, to stop arming China. This includes Britain and the EU, which are considering lifting an arms embargo imposed after
the 1989 Tiananmen Square Massacre.
But Japan's response to China's rise has several other dimensions. Before visiting Israel, Machimura went to Moscow.
Russia, another of China's old enemies, shares Tokyo's worries about Beijing's regional ambitions. Bilateral trade is expanding, with Japanese investment flowing into Russia's energy and automotive sectors. Military contacts are also growing.
Moscow announced this month that a new ?6 billion (US$11.3 billion) oil pipeline from eastern Siberia would run to the Pacific coast, allowing access to Japan, rather than to Daqing, in northeast China.
Russian President Vladimir Putin is expected to visit Tokyo soon. And high-level talks have even recommenced over a 60-year-old territorial dispute.
Russian Foreign Minister Sergei Lavrov said Moscow wanted to clear away old disagreements.
"The main thing now is to seek full cooperation in all spheres," he told Machimura.
This is a big change. Exactly 100 years ago this month, Japan was destroying Russia's Pacific fleet. Hostilities continued through much of the 20th century.
Japan's unusual political and diplomatic assertiveness is being matched militarily despite its post-war pacifist Constitution.