Eighteen string Robab: Eighteen string Robab is one of the original Iranian music in the northern regions of Sistan and Baluchestan, as well as neighboring countries such as Pakistan, Tajikistan and Afghanistan. it is one of the eighteen stringed- percussion instruments that can be played with a plectrum instrument. History of Eighteen string Robab: Due to the vastness and richness of the music culture of the Makran region, compared to the border region in Balochistan, it can be said that Rabab is not originally a Balochi instrument. Rabab has entered Baluchi music due to its proximity to Afghanistan and parts of Pakistan, as well as its resemblance to Baluchi instruments. Today, eighteen-string Robab one of the most important instruments in accompanying the songs and dhikrs of Darwish circles in Naqshbandiyyah of Saravan district. The poems used in the singing in their circles include Rast- saz magham, Jaran, Shirbam, Gorsaz, Khorman Saz, and others. Rabab is usually played with the tambourine. Due to the small number of Rabab musicians compared to other Balochi instruments and the fact that Rabab is mostly performed in certain musical positions, it can be inferred that Rabab cannot be a Balochi instrument. Today, the eighteen-string rabab is almost obsolete, and the five-string robab is also common in the village of Pirabad in Balochistan. As the number of Robab player is less in this region and just used to perform some distinct music Magham, it can be inferred that it is not a Balochi instrument in fact Structural features of the eighteenth rabab: In general, Rabab is a shape looks like Persian Tar and Sistani Ghichak. In fact, it has a two-part elongated bowl that has a short handle. Rabab bowl: It has two parts. The lower part of the bowl is larger and covered with deer skin. The upper part of the bowl, which leads to the handle, is also covered with a wooden plate. The two-part reverberation bowl, handle and claws are made of integrated mulberry wood. The plate is also made of mulberry wood. handle: The handle is attached to the upper part of the bowl which its inside is empty and the inner space is connected to the two-part bowl. Earphone: Two groups of earphones are divided into two groups of Rabab chords on the sides of the instrument. The main strings are located in the hook section and the sub-strings are located on the side and top of the large bulk bowl. The earphones are made of wood. chords: chords are categorized in two main and secondary groups. There are 6 main strings that are connected to the tailpiece, and on the other hand, after passing through the pallet and the vault, they are connected to the earphones on the nest section. The vocals are also connected to the tailpiece. On the other hand, after passing through the holes located in the body of the vault and the side pallets, attached to the inner part of bowel by the holes created on the wooden plate in the upper part of the bowl and handle, then connect to the alternative earphones. Each chord has a sub-pallet, and the holes are located next to them. In this case, replacing the strings is difficult. The number of sub-chords is 12 or 13. Just main chords are beaten by plectrum, and the sub-chords sound like vocals with the main chords. The main string number 1, 2 and 3 is made of nylon wires. string No. 4 is made of thick nylon wire and the fifth and sixth strings are made of steel wires with a diameter of 0.18 mm. In order to maintain the balance and tolerate the pressure of relatively 18 or 19 thick chords of Rabab on the vault and the skin, the thin strap of the vault is connected to the earphones. pallet: it is a narrow excrescence of the handle. Sometimes there is a thin stick on the pallet that is placed in the groove of the handle. The pallet is also made of mulberry tree. Tailpiece: it has two wooden pins frets: Three or four frets are tied on the handle of the rabab. But the executive limits of the frets are more than this number. Frets is used to guide the musician to create a symmetry between the sounds and the performance of different degrees of music, and the rabab can be played without frets just like lute. Executive technique: The great rababs are called Shah Rabab and the smaller ones are called Zilcheh. The main chords are played with a plectrum. The bass sound and the special structure of the rabab limit the right-hand technique. Due to the thickness of the chords, the bass tune-up and the presence of 18 chords in the structure of the rabab, a single plectrum must be used. Fine and Dorab techniques are also less commonly used. Left hand performance technique: The sound is with the impact of three fingers of the left hand. The fourth finger and thumb are not used for tapping on the strings. Also, due to the thick structure of the chords, vibrating, glissando, digging and talking, is less applied. Rabab are tuned in different ways, but there is also the main and fixed tune, which is known as the mother tune (narrated by Musa Zangshahi) or the right string tune (narrated by Darvish Abdul Raouf Sahebzadeh). Most of the Maghams are played with this tune. Administration of eighteen- string Robab: The dhikr circles of Naqshbandi Saheban dervishes in the villages around Saravan, which is the gathering place of Naqshbandiyya dervishes. Tambourine and sometimes even Binjo are accompined with Robab It is used in weddings and circumcisions in the Sarhad areas and is performed indoors.  Guatemalan music therapy rituals: In the southern and central regions of Baluchistan, Rabab is used as a solo and harmonica. Generally, one or two Robab are used to harmonize Baluchi instruments. musicians: Darvish Mohammad Sahebzadeh Musa Zangshahi Darwish Abdul Rauf Sahebzadeh