Japan’s national core consumer price index (CPI) accelerated in September 2026, with year-over-year growth reaching 2.1%, up from 1.7% in August. The data, updated on 22 October 2026, show that underlying inflationary pressures strengthened at the end of the third quarter.
The figures are based on a year-over-year comparison, measuring price changes in each month against the same month a year earlier. The “previous” reading of 1.7% reflects August’s increase versus August a year before, while the “actual” 2.1% reading captures September’s gain against September of the prior year. The move from 1.7% to 2.1% indicates a noticeable pickup in core price growth across Japan’s economy during September.
The latest core CPI data will likely feed into ongoing market discussions about the trajectory of Japan’s inflation trend and its implications for future policy decisions, as investors and analysts monitor whether this acceleration proves persistent or temporary.