Tokyo CPI (leading indicator) in Japan

It is the Consumer Price Index covering only Tokyo's 23 special wards, published by Japan's Statistics Bureau. It acts as a lead for the national CPI, as it is released about a month ahead of the national figure for the same period.

It is calculated with the same methodology and basket as the national CPI but using only prices collected in Tokyo. Three year-on-year measures are released: headline, excluding fresh food (the Japanese core) and excluding fresh food and energy (core-core).

By leading the national figure, the market treats it as an early signal of Japanese inflation and Bank of Japan policy; a hotter-than-expected core reading feeds expectations of stimulus withdrawal and tends to support the yen.

It covers only Tokyo, so it misses price differences across the rest of the country and can diverge from the national figure; it is subject to revisions and sensitive to one-off factors in the capital.