Japan's trade surplus fell in 2005, with high oil prices overshadowing growth in exports.
Soaring energy costs boosted Japanese imports last year
Its surplus shrank by 26.5% to 8.8 trillion yen ($75.8bn; £42.4bn) last year, the first fall in four years.
Japanese exports grew by 7%, but they were swallowed up by a soaring energy bill as imports of crude oil rose 45% and gas rose 20%.
Economists say the decline now means that China has the world's biggest trade surplus, at $102bn (£58bn).
Russia has yet to produce its figures for 2005, but is expected to outstrip both countries thanks to soaring oil and gas costs through the year.
Despite the lower surplus, most Japanese exports saw healthy growth in 2005, and rising imports indicated that domestic consumption had picked up.
"The latest trade figures confirm that Japan's economy is recovering steadily and modestly," said Hiroaki Muto, senior economist at Sumitomo Mitsui Asset Management.
Official figures released on Wednesday showed that the Chinese economy grew by 10% in 2005.
Experts say that China may now have overtaken France and the UK to become the world's fourth-largest economy.