The hardest instrument
You can measure how hard it is to play the instrument by looking at how hard it is to understand the basics or how hard it is to master the instrument. For example it is quite easy to learn how to play easy songs and chords on the guitar, but when you get to more complicated melodies it becomes very difficult. The hardest instrument to play is oboe. First of all this instrument requires a lot more of maintenance than most of other instruments. It is also very hard to tune this object, but without making it sound right, you can not learn even basics. After you finally tune you realise that it is very counterintuitive. For example in order to play higher notes you have to lower your hand. Oboe is considered the hardest instrument in the world. https://higherhz.com/hardest-instruments-to-learn-play-master/