Translation of the Tamil Wikipedia page
The yazh is the most important of the ancient musical instruments. Yazh means it is made of "nerves" (strings). The basic classifications of musical instruments are those made with hide, those contaning holes, those with strings and meedatru karuvi (?). Of these, the stringed instrument yazh was the first musical instrument played by Tamils.
The yazh was the first instrument based on which other stringed instruments were developed. This instrument has become completely forgotten and is basically an ancestor of the veena. Yazh is also called "kellvi" (question mark) due to its shape.
One of the instruments in use in hilly regions was the bow (?). When the bow is strung and arrow released, the sound that was made was the source for the creation of the yazh. This bow gave rise to the "bow lute" (vil yazh). Though the Paditrupattu (a book of poems) says that the yazh originated in forest land, its more appropriate origin is in the hilly regions because hunting was a major occupation only in hilly regions.
This vil yazh, because of human effort and labour, has multiple types.
Even though descriptive text can be found in ancient literature, the absence of drawings or sculptures stops one from exactly knowing the shape and structure of the yazh; it can only be postulated. Sangam literature (puranaanooru, kalithogai, paripadal and aatrupadai books, thirukkural, silappadhikaram, perungadai, jeevagachintamani etc. epics and spiritual literature) contain information about the yazh. Still, we can only make out the types as peri yazh (big), siri yazh (small), magara yazh (red), sakoda yazh (?) but we don't know the real structure.
Pallava temples (Kanchi Kailasnath, Rajaraja Chola's temple etc.) have yazh sculptures.
Even though the yazh originated in hilly landscapes, it spread to other regions as well. Players of this instrument were called "banars" and literature talks about them. Of the yazh players, there were two divisions - big and small yazh players. Based on the musicians there are two books in Sangam literature using which we can understand the importance of these musicians.
These books describe how the kings praised and revered these musicians. This is an accompanying instrument while singing. From being a common man's instrument it became one worthy of worship.
Tamilians gave prime importance to music that originated from the yazh. Because of this, starting from one string, 3, 5, 7... 1000-stringed yazh came into being. Though the shape was not initially a consideration, different kinds of red yazh came into being. The yazh grew like this until the 9th century A.D. Afterwards it developed into the veena. This veena is today one of the foremost instruments in music.
Yazh and Veena
In Sangam literature and early epics, only the yazh is mentioned. Later on, in Bhakti literature, both yazh and veena are described as reflected in ‘seven-music yazh’ ‘veena along with bow’ which are lines from Manickavasagar’s poem. 9 century AD ‘s Seevaga Chinthamani line ‘Veena aka Yazh and song’ indicates yazh-along-with-a-plectrum as a veena. While explaining the line ‘Seevagan won against vellimalai (silver mountain) Verkannaal’, the translator means that Seevagan won with yazh and song. Through this we can infer that yazh was referred to as veena and developed as an independent musical instrument. In Silappadikaaram, there is a line which says ‘Naarada’s veena and song’. Adiyaarku Nallar translates this as Yazh. From around 1800 years ago, the word veena has been in use in Tamil. Even Ilango-adigal uses the line ‘for auspicious beginnings along with the sound of veena’. The word veena here refers to the human body. So the word veena was possibly in use in multiple contexts. Later on, the word came to refer to the musical instrument.
In Akananuru, Purananuru, natrinai, Perumpaanatruppatai, Porunaratruppatai, Cirupanatruppatai, Paripaatal, Malaipatukataam etc. describe and have various references of how to play the yazh, types of yazh and their structure and parts. Silapadikaaram vividly narrates the types of yazh, parts of a yazh, how to tune the yazh and how to play it. In Seevaga Chintamani, while detailing a contest between a lady who is a Gandarvadatta musician and Seevagan, there are mentions of what can go wrong with the yazh, the grammar needed to play the yazh etc. The writings of the Thirumarai teachers, in multiple places the yazh is said to be used for worship. Thirugnana Sambandar’s Thevaaram has been translated beautifully on the yazh by Thiruneelakanda yazhpaanar. In 1947, Swami Vipulaananda, a Sri Lankan, has compiled many research pieces into his book called Yazh nool.
The yazh is a stringed instrument. The lowest portion is the resonator, which is made from the Thannakku tree. This is boat-shaped. The top is covered by a layer of skin called sheet-skin. There is a rod that is positioned across this skin, which has pegs. Strings are attached to the top of the stem. Some yazh had mechanisms to tighten the strings. In some cases the positions of the strings were moveable, and the sound was thus adjusted. Sangam literature refers to various parts of the yazh by naming them.
Song which describes yazh
Yazh’s shape according to Perumpaanaatrupadai
“Yazh, which is made of skin which is red like a split trumpet flower, with a sheet covering that is smooth like it was derived from the betel-nut tree, its mouth looks like a the mouth of a dried-up spring. The strings look taut like bangles on the hands of much-wearied girls. It has a big long stem like a blue-mountain. The strings look like they were made of molten gold.” With these words, we can picture how the yazh looked.
Yazh according to Adiyaarku Nallaar
"Each person measures about 8 times their hand-measure (i.e., from tip of mid-finger to thumb, at max stretch). The Periyazh is 12 hand-measures. It’s width is one hand-measure(??)" says Nallaar, who lived in the 12th century.
Types of yazh
Kallaadam, an ancient text from 9 th century talks about the following types of yazh: 1. Bow yazh – 21 strings 2. Periyazh – 21 strings 3. Makara yazh or Red yazh – 17 or 19 strings 4. Sakoda yazh – 16 strings 5. Keechaka yazh – 100 strings 6. Sengotti yazh – 7 strings 7. Seeri yazh – 7 strings Other than these, there are also Naarada yazh (100 strings), Naarada periyazh, ancient periyazh (100 strings), thumburu yazh, medicinal yazh (deva yazh), antique (1000 strings), parrot yazh, lute yazh, hilly yazh, desert yazh, forest yazh, fertile-land yazh, seashore yazh (These are the five kinds of land described in ancient Tamil literature, each having its own yazh) and many such types of yazh described in ancient literature. Makara yazh is said to have originated in Greece (Yavana). Mr. A. Raghavan from Saathaankulam refers to 24 types of yazh in his book: 1. Bow yazh 2. Seeri yazh 3. Sengotti yazh 4. Periyazh 5. Sakoda yazh 6. Makara yazh (lancet-flag yazh, Kaama-flag yazh, Varna’s-vehicle yazh) In the Tamil Conference Exhibition held in Coimbatore, the following types of yazhs, which are ~700 years old, were on display: 1. Sengotti yazh 2. Bull yazh (likely bull-skin yazh?) 3. Peacock yazh 4. Mayuri yazh
How to play
Each string of the yazh helps sharpen each sruti (?). Only sruti surs can be played on the yazh. The yazh was tuned using the Sembaalai or harikaamboji melam (?) first, then they played using grihabedas (?).
Today yazh is out of favor and not in use. Experts feel the rise of the veena has been the cause of the fall of the yazh. They also opine that over a period of centuries the yazh slowly transformed into the veena. It is possible to play subtle srutis using the veena. Also, the veena has metallic strings with bridges (frets?). Being easier to play and learn, and also being able to produce more nuanced sounds, were the reasons for the veena’s popularity, but still, both the yazh and the veena apparently coexisted for many centuries.