The country's central bank on Thursday (September 22) said it would keep rates unchanged and ultra-low.
That's in contrast with its peers.
Only a day earlier the U.S. Federal Reserve delivered a third straight increase, and signalled more to come.
Bank of Japan governor Haruhiko Kuroda says the country's economy still needs support to recover from the global health crisis:
"There's absolutely no change to our stance of maintaining easy monetary policy for the time being. We won't be raising interest rates for the time being."
Japan now has markedly lower rates than other major economies, and that is punishing the yen.
The Japanese currency sank to a fresh 24-year low against the dollar following Thursday's news.
Within hours, officials said they had intervened in currency markets to prop up the yen.
It's the first time that's happened since 1998.
Kuroda said the BoJ would play its part too:
"Recent yen falls make it difficult for firms to set business plans and heighten uncertainty about the future. They are negative and undesirable for Japan's economy. The Bank of Japan will coordinate closely with the government, and closely monitor the currency market moves and the impact they have on the economy and prices."
The dollar plunged around 2% against the yen immediately after news of the intervention.
However, it later recovered some ground, and analysts doubt whether Tokyo can halt the yen's slide for long.
Authorities didn't say how much they had spent supporting the currency, or whether Washington had consented to the move.
