By Agence France-Presse
Japan logged a surplus in March of 623.1 billion yen ($5.9 billion) with the US, down 0.2 percent, as imports of American-made cars and aircraft climbed, according to the finance ministry data.
The fresh data comes as Japanese Prime Minister Shinzo Abe and US President Donald Trump thrash out difficulties in their trade relations at a summit in Mar-a-Lago.
Larry Kudlow, Trump's top economic advisor, has cautioned that while "Japan is a great friend and ally", there are "certain disagreements with respect to some of the trading issues, we'll iron those out hopefully".
To its obvious displeasure, Japan was not on the list of countries exempt from Trump's announced tariffs on steel and aluminium.
And Trump tweeted on Friday that Japan "has hit us hard on trade for years".
Japan's overall trade surplus was 797.3 billion yen in March, up 32.1 percent year-on-year -- the second straight monthly surplus after logging a deficit in January.
Exports edged up 2.1 percent due to growth in demand for cars and chip-making equipment, while imports slid 0.6 percent year-on-year.
The yen was on average 6.3 percent higher against the dollar in March compared to the same month a year earlier, the ministry said.
Still, the costs of importing petroleum products and liquefied natural gas increased because of higher prices globally, the ministry said.
Car imports also rose both in costs and volume.