Bindusara was the son of cgm's wife named "Durdhara".
There is a small story about him.
Chanakya use to mix a little amount of poision in cgm's food for immunity. So that cgm could resist the adverse affect of the weapons by his enemies.
Cgm was not knowing about it and once was taking food wid her 7 month pregnant wife Durdhara,as she eaten that poision mixed food cant tolerate that and died in a second.
Chanakya entered the room cut the stomach of the died Durdhara and take out the baby.
The poision was hard so it has reached babies head and he got a blue mark on his head so named "Bindusara" .