PARIS — Japan looked like the model for economic revival. Growth was back on track. The stock market was surging. Inflation, which had eluded Japan for decades, was even returning.

But Japan’s grand economic experiment, a combination of fiscal discipline and monetary stimulus, is collapsing. On Monday, the country unexpectedly fell into recession, a downturn that has painful implications for the rest of the world.

Japan’s unorthodox strategy was supposed to offer a road map for other troubled economies, notably Europe. Fiscal belt-tightening and tax increases, while leaning on the central bank to pump money into the economy, was expected to help overcome a malaise.

The formula, though, has failed to ignite a meaningful recovery in Japan — and has even added to its woes. Europe must now decide whether to follow Japan’s lead by injecting more money into the economy, as the region’s central bank considers a similarly aggressive bond-buying campaign known as quantitative easing. And the United States, which just ended its own six-year stimulus effort, doesn’t offer much of a cushion should other economies stumble further.