Gesang Martohartono was an Indonesian singer-songwriter from central Java. He is the composer of the "Bengawan Solo," famous song throughout Indonesia, Japan, part of Asia, and some other countries. The song is almost synonymous with the kroncong style of Javanese music. Martohartono was most commonly known simply as Gesang.

"Bengawan Solo" is an Indonesian song written by Gesang Martohartono in 1940. The song is a description of the longest river in Java, Solo River. The song became popular in Indonesia during the Second World War and was one of the songs promoted nationally in the newly-independent country after the war.