Japan CPI: the national inflation report and the yen

Japan CPI, the national consumer price index, is the monthly measure of how much the prices that Japanese households pay have risen, published by the Statistics Bureau of Japan. The Bank of Japan's 2% target is set on this index, so a surprise changes what the market expects from the next BoJ meeting and, through that, the yen.

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By Mike. Explanation updated 2 Oct 2026; the dates and moves below update with the research.

Japan CPI in short

Next release: Not on our calendar yet. It appears once the date is confirmed.
Published by: Statistics Bureau of Japan
When: Monthly, on the Friday of the week that includes the 19th, at 8:30 in the morning Tokyo time, for the month before. Japan does not change its clocks, so in Amsterdam it lands at 01:30 for most of the year and at 00:30 in the European winter, from late October to late March.
Currency: Japanese yen (JPY)
Impact: High: one of the releases that can move the currency on its own
The line read first: CPI without fresh food, on the year: the measure called core in Japan
Central bank that watches it: The Bank of Japan, whose price stability target is 2% on the CPI
Covers: The month before, so the September release holds August's prices
Comes after: Tokyo CPI for the same month, about three weeks earlier

What is in Japan CPI

The Statistics Bureau, part of the Ministry of Internal Affairs and Communications, prices a basket of close to 600 items across the country. The release gives the change on the year for all items and for measures that leave out the parts that swing most.

All items less fresh food is the measure the market calls core in Japan. It leaves out fresh food, whose prices move with the weather and the harvest.

All items less fresh food and energy goes one step further and also removes electricity, gas, propane, kerosene and petrol. It is the line in the report that says most about the trend underneath.

Why Japan CPI moves the yen

The Bank of Japan's price stability target is 2% on the yearly change in the CPI. Each release shows how close inflation is to that target, and the BoJ's own statements discuss the index without fresh food by name.

A figure above the forecast makes another BoJ rate step more likely, Japanese yields go up and the yen tends to firm. A figure below it does the opposite.

Government measures, such as support for energy bills, can push the index up or down for months at a time. The BoJ looks through those effects to what it calls underlying inflation, and the market tries to do the same.

How to read Japan CPI against the forecast

The market has priced the forecast before the release. What moves the yen is the distance between the figure and that forecast, and on core CPI a single tenth of a percentage point can be enough.

Tokyo CPI for the same month came out about three weeks earlier, so the market has already adjusted its view. A national figure that breaks from what Tokyo showed is the one that tends to move the yen.

Read the figure against the path in the Bank of Japan's latest Outlook Report as well. Inflation that runs ahead of the Bank's own forecast matters more than inflation that matches it.

What the Japanese yen did on the last release days

Measured on our own prices: the Japanese yen against the basket of the eight majors, from the London opening before the release to the one after it, so the release sits inside the window. Anything else that came out between those two openings is in it too, so a day with more news says less about this release alone.

Release	Amsterdam	Measured	JPY vs basket
18 Sept 2026	01:30	17 Sept to 18 Sept	-0.97%

For scale: on an ordinary day the Japanese yen moves 0.24% against the basket from one London opening to the next, either way, on average over the 250 trading days since 14 Oct 2025.

The forecast, the figure itself and what it changed in our view of the currency are in the app, next to the research.

Questions about Japan CPI

What time is Japan CPI released?

At 8:30 in the morning Tokyo time, on the Friday of the week that includes the 19th of the month. In Amsterdam that is 01:30 for most of the year and 00:30 in the European winter.

What is core CPI in Japan?

In Japan, core CPI usually means all items less fresh food. The measure that also leaves out energy is often called core-core by traders, and it says more about the trend.

What is the difference between Japan CPI and Tokyo CPI?

Tokyo CPI covers the 23 wards of Tokyo and comes out first, as a preliminary figure for the current month. Japan CPI covers the whole country and comes out about three weeks later for the same month.

Does a high Japan CPI make the yen go up?

Usually, when it is higher than forecast, because it makes a BoJ rate step more likely. A figure that is high but exactly as forecast moves little, because it was already priced.