The acceleration was driven in particular by rising prices for processed foods against a backdrop of soaring energy costs owing to the conflict in the Middle East.
Excluding volatile fresh produce, inflation was 2.1 percent, up from 1.7 percent in August, according to the internal affairs ministry reading.
The figure was in line with market expectations and above the 2.0 percent target set by the central bank, further raising chances of an interest rate hike.
“With underlying inflation back above the Bank of Japan’s 2 percent target, the case for further tightening remains on solid ground,” said Abhijit Surya of Capital Economics.
“News reports suggest that the Bank may revise up its inflation forecasts at its October meeting. That should set the stage for another hike in December.”
The BoJ already raised interest rates in mid-September, in line with other major central banks around the world, in an effort to counter strong inflationary pressures driven by soaring energy prices triggered by the Iran war.
A weak yen is also driving up the price of imported goods.
Rents and automobile-related costs also contributed to inflation, the data showed.
Surya, of Capital Economics, said rent inflation matched “its highest rate in nearly 25 years”.
But government support for petrol and electricity fees mitigated the impact on energy prices, according to the internal affairs ministry.
Excluding both food and energy, inflation stood at 2.4 percent, above market expectations, following a figure of 1.9 percent in August.
The government is trying to mitigate the impact of inflation on household purchasing power, notably with a massive stimulus package adopted at the end of 2025 and extensive tax breaks on energy.
Japanese Prime Minister Sanae Takaichi’s two predecessors were undone by anger over inflation.
The government said it would slash consumption tax on food products from eight percent to one percent for two years, starting in April.
However media reports said this will cost the government 10 trillion yen, or about US$63 billion, in lost tax revenues.