Idanthalai syllables (Sotkal), are those that are played on the left head of the Miruthangam. The left head is the generic name given to the side that does not contain a black circular area (Soru) and is not dependent on the handedness of the player i.e. it is called the Idanthalai (Left head) even if the player plays this part with the right hand.
The "Tha" note (Sollu) is played by striking the centre circular area of the Miruthangam's left head (Thopi), for a right handed player, with all four fingers and upper part of the palm. This note is flat.
In the standard "Sollkattu" the "Tha" doesn't posses any other notation names.
The "Thom" note is played by striking the edge of the centre circular area of the Miruthangam's left head (Thopi) with all four fingers of the palm. The fingers must immediately be lifted out to allow for the resonance.
The "Thom" has many variations in the name when it forms a group of Sollkattu for example:
1) Thalangku : Where the Thom is recited as Ku.
Say - Tha Lang, Ku
Play - Tha Chaapu Thom
2) Thakkum : Where the Thom is recited as Kum.
Say - Tha, Kum,
Play - Da, Thom,
3) Tharikida : Where the Thom is recited as Ki.
Say - Tha Ri Ki Da
Play - Thi Da Thom Thi
The "Gumakaramh" or Gum note is played by striking the top edge of the centre circular area of the Miruthangam's left head (Thopi) with all two to three fingers of the palm while simultaniously sliding the base of the palm upwards to produce a resonating sound.