“A Japan where every person can have hope for tomorrow” sounds like a fairly modest aspiration. But that was the wish that Shinzo Abe, the Japanese prime minister, expressed for the new Reiwa imperial era, which will begin on May 1, when Crown Prince Naruhito ascends to the imperial throne.

For Mr Abe, awakening a sense of optimism is part of a broader mission of national reinvigoration, in which symbolic moments like crowning a new emperor play an important part. The Japanese prime minister knows that his country faces a daunting array of challenges, including an ageing and shrinking population, a heavy debt burden and the threat of a rising — and potentially vengeful — China.

The success or failure of efforts to inject new dynamism into Japan will affect the whole world. As the most powerful democracy in Asia, and the world’s third largest economy, Japan is crucial to the global balance of power. If China is to become the leading power of the 21st century, it must first achieve unquestioned dominance of its own region — and Japan represents both a physical and a political obstacle to China’s ambitions. The offices of security officials in Tokyo often include the familiar map of Asia turned on its side, so that China is on the bottom, with its unfettered access to the Pacific Ocean, blocked by a thin sliver of land: the islands that make up Japan.