Japan's core inflation in September slowed below the 3% threshold for the first time in over a year but stayed above the central bank's target, keeping alive expectations that policymakers will phase out ultraeasy monetary policy.

The data will be among indicators the Bank of Japan will scrutinize at its two-day policy meeting ending on Oct. 31, when it will produce fresh quarterly growth and price forecasts.

"While inflation weakened in September, we think inflation will only fall below the BOJ's 2% target by the end of next year," said Marcel Thieliant, head of Asia-Pacific at Capital Economics.