Does the pipa have strings?

e,b,g,d,a,E on a six string guitar

There's nothing really "by the book" on this , the first basses had four strings cause of the upright ! Then someone had the idea of adding a fift string and a sixt and more and more... the most i've...

String instruments vibrate by when you pluck the strings the noise from them is bounced around the hallow in side of the instrument you are playing.

If mean what is standard 6 string tuning its B-E-A-D-G-C

it is cause the string bass has 4 strings so it belongs to the string familylol:D