Is there a special rule? Here's 4 female members who often sing the beginning of the title song of group.
The introduction part of the song should be catchy and impressive. So the listeners can fall for and keep listening to the song. This is why the beginning, the introduction part of song, is so important. Therefore, the staff and producers are deeply considering on who they are going to give the starting role. Here are 4 ladies who mainly do the first singer of groups' title songs or songs which were active on.
For the first singer of the song, nice singing capability, impressive voice and stable performing skills are needed. Nobody can't deny that the first singer of the song must be scary and nervous than any other members because the first singer should start the performance perfectly without any mistake.
Let's take a look who they are and just guess why they are chosen to be a first singer so often like that!
#1 F(x)'s Krystal (8 songs where Krystal starts the beginning / 9 songs which were active on since debut) - 89%
#2 TWICE's NaYeon (4/5) 80%
#3 Red Velvet's SeulGi (5/9) 56%
#4 SNSD's TaeYeon (11/20) 55%