The Subaru Sumo, known as the Libero in European markets except the UK, Norway, and Sweden, and as the Domingo in the Japanese market, was a microvan produced from 1983 to 1998. In Sweden, it was known as the Columbuss (buss means bus in Swedish), and in Taiwan the latter generation was marketed as the Estratto. It was also called the Subaru E10 and Subaru E12 respectively in some places, the names referring to the size of the engines. The Sumo shared many characteristics with the Sambar, except it had extended front and rear bumpers and a larger engine borrowed from the Subaru Justy. Because of these modifications, it didn't conform to kei car regulations, which stipulate the maximum dimensions of the vehicle and the maximum engine displacement requirements, which then determine the vehicle tax to be paid.
It was launched with the option of four-wheel drive and powered by 1.0- and 1.2-litre 3-cylinder EF engines based on those used in the Subaru Justy although in the van they were rear mounted. Somewhat unusual for a microvan, the 1,200cc Sumo could be ordered with selectable 4WD, operated via a gear stick mounted button. In normal driving conditions, only the rear wheels were driven, as there was no central differential to allow highway driving in 4WD mode. In 1994, Subaru's Full Time 4WD (S-AWD) was added to the options list with the ECVT transmission only and a viscous coupling. An oil cooler was installed on European versions to better facilitate light duty towing.