The Bank of Japan produce their own data on inflation rates in the country.

The key rate the Bank watches is the 'Weighted Median' y/y. It has hit 2% in the latest data, for September 2023, from 1.8% in August.

  • this data point is used by the BOJ as a measure of broad inflation
  • at 2% its hit a record high since comparable data became available in 2001

The Bank of Japan next meet on October 30 and 31, and will publish fresh inflation forecasts as part of the meeting. Its likely that the Bank will revise up its inflation forecasts. Discussion is also likely on capped JGB rates.

The BOJ has said, repeatedly, that it'll keep ultra-low interest rates until 2% inflation can be achieved on a sustained and stable manner backed by solid consumption and wage increases.

boj 2 % inflation target 25 October 2023


The weighted median is the inflation rate of items at the middle of the price changes, or around the 50th percentile point of the distribution. It was around around zero for the past twenty years but began inching higher last year. Higher raw material costs were blamed. The weighted median inflation rate is used by the Bank to indicate how broadly prices are rising, it's a closely watched measure at the BOJ for clues on the broad price trend.