The consumer price index shows how much the cost of buying the same basket of goods and services as households bought in the base period has changed. The nationwide index for a month is, as a rule, published on the Friday of the week that includes the 19th of the following month.
Indexes that leave out some items are also compiled, such as the "all items, less fresh food" index, which excludes fresh food because its prices move sharply. Japan's inflation-indexed JGBs reference the nationwide consumer price index (all items, less fresh food).