Mitsubishi bought a cargo of Vietnamese crude for loading in September on behalf of Japanese utilities at a record premium for the grade, traders said.
The purchase comes after Nippon Steel bought a liquefied natural gas (LNG) cargo at the highest price ever paid in Japan. The world's No 2 LNG importer is scrambling for power fuels as a global heatwave drives electricity demand this summer.
"Japan has a power shortage, so it has to pay up. Other countries also have the same problem now, especially in Europe," one of the traders said.
Mitsubishi paid a premium of US$21 a barrel to dated Brent for the 300,000-barrel cargo of Vietnamese Chim Sao crude, said two of the traders who regularly track the grade.
That puts the cost of the cargo at about US$127 a barrel based on current Brent prices, or US$38.1 million.
Mitsubishi does not comment on individual deals, a spokesperson said.
Japan last imported Chim Sao crude in February and April, according to Refinitiv data.