Inflation in Tokyo continued to rise further than the central bank's target to a new near 42-year high in January.
Core consumer prices in the Japanese capital, a leading indicator of nationwide inflation, rose 4.3% this month from a revised 3.9% reading in December.
The reading was the strongest on record since 1981 and exceeded analysts' estimates for a 4.2% increase.
The figures were released amid growing speculation that the Bank of Japan (BOJ) will change its policy stance after Governor Haruhiko Kuroda ends his term in April.
Following this publication, the yen jumped 0.3% against the US dollar to trade at around 129.70 in the Asian session.
Meanwhile, analysts see the possibility that the yen could break below 125.00 against the yen as expectations for a BOJ policy change remain high.
At its latest policy meeting last week, the central bank did not offer any hawkish indication of its future policy direction, instead maintaining its policy stance to remain loose.
