The Japanese prime minister's state visit to China last week was therefore a triumph of persistence — six years of an incredible political tour de force.

Careful, though. Abe is on probation (just take a look at that handshake at the Diaoyutai State Guesthouse). China is now testing how far a more constructive relation with Japan may go in the context of a rapidly changing geopolitical landscape. The Chinese know that Abe flunked a similar test with Russia, which will probably cost him one of the apparently dearest objectives of his political career.

And beware this red herring: The idea that Beijing suddenly warmed up to closer relations with Japan as a result of China's weakening economy and a trade dispute with the U.S. is arrant nonsense.

In fact, China's economy is in good shape. The gross domestic product growth was 6.7 percent in the first three quarters of this year. Inflation is stable (2.5 percent in September), public finances are sound (a budget deficit of 3 percent of GDP and public debt of $5.2 trillion, or 47.6 percent of GDP), and there is a trade surplus on goods and services of $70 billion, with a whopping $3 trillion stashed in foreign exchange reserves.

China, clearly, does not need Japan for the steady growth of its huge and rapidly expanding domestic market. And neither is China desperate for Japanese investments. According to the latest United Nations numbers, China was the world's largest recipient of foreign direct investments in the first half of this year. During that period, China got $70 billion in FDI inflows, a 6 percent increase from the year-earlier, despite a 41 percent global decline for trans-border direct investments.

It is also ridiculous to think that China needed Japan as an ally in its trade dispute with the U.S.

No, Abe's comment in 2012 about the importance of China for Japan's economic growth is more valid today than six years ago, and his Herculean efforts to patch up relations with China are testimony to his extraordinary dedication to his country's welfare.

Japan's $206.1 billion in bilateral trade with China during the first eight months of this year is by far the largest segment of Tokyo's foreign trade transactions. The U.S., with a bilateral trade business of $143.8 billion, comes in as a distant second.