Japan has recorded its first trade surplus in three years after the weaker yen boosted exports and cheaper oil prices lowered its import bill. The trade balance came in at 229.3 billion yen in March, beating market expectations for a surplus of 44.6 billion yen. Exports rose by 8.5 per cent from a year earlier, while imports fell by 14.5 per cent.Japan's trade balance fell into the red after the March 2011 earthquake and disaster led to the closure of the country's nuclear plants.