•: Stops, |: Passes through Construction of the line commenced from both Oita and Kumamoto in 1914, with connection being achieved with the opening of the Miyaji - Tamarai section in 1928.

The 22.5 km Kumamoto - Higoozu section was electrified in 1999.

In 1990-91, the line was severed for a year by landslides caused by torrential rain, with a further eight-month period of disruption occurring in 1993-94.

A three-month period of disruption occurred in 2004, and the line was severed from July 2012 until August 2013 due to further landslides induced by torrential rainfall.

In 2016, the Kumamoto Earthquakes damage resulted in the closure of the section between Higo Ozu and Aso.