The Dilruba is a smaller and modified version of the Taus. The reason for its creation was predominantly due to the practicality of carrying it for the soldiers and warriors who served in the army of the Tenth Guru Sahib, as all soldiers kept their instruments with them at all times. The Taus had storage issues due to its size and the Dilruba resolved these issues for the Sikhs as it is much smaller in size and much cheaper to produce compared to the Taus.
Dilruba is also the easiest and lightest instrument to play and it is incredible simple to understand. It takes simply 10 minutes to pick up and start playing.
Below is an image of the Dilruba as approved by Guru Gobind Singh Ji:
