Imports slipped 2.5 per cent from the same month a year earlier to 10.3 trillion yen ($A95 billion), while exports climbed 16.8 per cent to 9.19 trillion yen, the finance ministry reported on Wednesday.
That left a deficit of 1.15 trillion yen, less than half the trade deficit recorded a year earlier.
Analysts noted that a key reason for the big jump early in 2026 was because the Lunar New Year occurs later than usual, falling on February 17.
Japan's economy depends heavily on exports and dramatic increases in tariffs by US President Donald Trump have taken a toll.
The economy expanded at an anaemic 0.2 per cent annual pace in the last quarter, with growth for 2025 at just 1.1 per cent as weaker exports offset a modest increase in private consumption.
Exports to the US fell 0.5 per cent in January, the latest data showed, while imports from the US rose three per cent.
Exports to the US of vehicles, which account for about a third of the total, fell nearly 10 per cent.
Despite antagonisms with Beijing over comments by Prime Minister Sanae Takaichi about Taiwan, Japan's exports to China jumped 32 per cent year-on-year in January.
Exports to all of Asia were robust, surging 26 per cent, the data show.
Imports of semiconductors and other computer components showed the fastest growth, likely reflecting the impact of the boom in artificial intelligence, which has supercharged demand for data centre equipment and computer chips.
"But the currently strong tailwind from the US AI boom is unlikely to last, suggesting that gains in exports to Asia excluding China will moderate," Norihiro Yamaguchi of Oxford Economics said in a commentary.
He said exports were "highly likely to moderate" in March.
22°C