The trade deficit for last month totaled 1.3 trillion yen ($12 billion), the Japanese Finance Ministry said in a report.
That marked the third straight month of a trade deficit for the world's third largest economy.
In October, the nation managed to eke out a trade surplus, largely because falling crude oil prices offset a drop in exports.
Both Japan's exports and imports to China fell in January, according to the ministry data. Exports and imports to the U.S. also fell for the month.
The outbreak of CODIV-19 that began late last year, halting factory production and crimping travel, has been worsening the worries about China's economy, a key driver of regional growth.
Such worries added to those set off earlier by the trade policies of President Donald Trump.