TOKYO — Japan’s economy has contracted so many times in the last few years that the meaning of recession has started to blur. If an economy is shrinking almost as often as it is growing, what does any single downturn say about its health?

Now Japan appears to be faltering again.

After a decline in the second quarter, there are signs that output may have slipped again in the third, driven down in part by a slowing Chinese economy. Economists expect any recession to be short and shallow, but the deeper lesson looks more troubling: Nearly three years after Prime Minister Shinzo Abe gained office on a pledge to end economic stagnation, a decisive break with the past still appears far off.

“The potential growth rate is close to zero, so any small shock can put the economy into recession,” said Masamichi Adachi, the chief Japan economist at JPMorgan Chase. “Growth expectations are anemic.”

As a result, some economists are betting that the Bank of Japan, which has been pumping vast amounts of money into the economy by buying up government debt, will pull the trigger on more stimulus at its next board meeting on Friday.