I became a big fan of this song, very much so especially after the Ilaiyaraaja show in Chennai. And SPB was just awesome during the show. He was singing perfectly with ease.
"Pothi vecha malligai mottu" from Manvaasanai
The song is in 3/4 ( tha ki ta || ). I wouldn't attach any ragam to it because it changes shades during the interludes and charanams. But I guess the pallavi is in sudha dhanyasi - not sure though.
Some portions which I love in this song:
The prelude: Prelude is too good - very soothing and very konji-fying, especially the starting violin and the piece just before the pallavi.
Pallavi: The song doesn't start on the first count (start of the bar), but rather 2 counts later. And the accompanying music also plays along with the voice only after the 2 counts and that too for the 1st line alone and remains silent for the next line. This creates a good effect. The tabla also doesn't play for the 1st count, but only for the second and third counts. This type of tabla beat can also be observed in "mounamana neram" from Salangai Oli.
First interlude: I like the this interlude towards the end where the bass plays beautiful counter points(??) with the guitar and nadhaswaram. It is just awesome, mainly due to the bass track, just before and during the nadhaswaram part.
Pallavi after First Charanam: Now there would not be any beats but just hand claps for the 1st and 2nd counts. During the IR show in chennai, the percussionist started clapping and very soon the whole crowd got engrossed and began to clap according to the beat.
This again assured me that 3/4 is the most natural rhythm to the human - an observation which I had made. Even our heart beats in 3/4 , I believe! Not to mention Ilaiyaraaja's "Paruvame" song - with the lead couple jogging around in 3/4 timing. Normally if one were to compose for a jogging situation, composers might choose 4/4 ( tha ka thi mi | tha ka ja nu || ). But here IR has chosen 3/4 and it has suited very well. Similarly in the "Om Namaha" song from Idhyathai Thirudathe, you can listen to the heart beat sounds in 7/8 timing ( tha ki ta | tha ka thi mi || ) where normally anyone would use 3/4 or 4/4 for heart beats. That is Ilaiyaraaja for you.