Businesses across Japan are paying more for the goods they buy and sell. In August, these prices jumped faster than economists had predicted, signaling that inflation—when the cost of things generally goes up—remains a real problem. This unexpected surge gives the Bank of Japan (the country's central bank, similar to the U.S. Federal Reserve) good reason to keep making borrowing more expensive through higher interest rates.
When the central bank raises interest rates, it makes loans costlier for businesses and consumers, which typically slows down spending and helps cool down rising prices. The stronger-than-expected price gains suggest inflation is still pushing upward, so the Bank of Japan appears ready to continue tightening its grip on the money supply to prevent prices from spiraling out of control.