The Tam Thap Luc is a sort of zither with thirty-six brass strings as it is called. It has the shape of an isosceles trapezoid, with a slightly convex sound board made of light, porous, unvarnished wood.
The bridges and sides are made of hardwood. The bottom is flat. There are two staggered lines of 18 bridges on the sound board. The bridges on the left have hooks to which the strings are attached; those on the right have pegs for tuning. The strings, made of metal, are struck with two thin flexible bamboo sticks tipped with felt.
The playing technique includes a quick run, vibrato, stopping, and pressing. The tones are bright and merry and the notes of an arpeggio can be played in swift succession or simultaneously.
The Tam Thap Luc plays an important role in the band accompanying cheo and cai luong operas. It can also be played to accompany instrument solos, singing, or as part of an orchestra. Recently, more strings have been added so that all semi-tones can be played.