From what I know
China: There was a girlgroup in 2016 (I forgot their name) where 4 girls had been in, they used to be 4-6 years old back than (there was a clip of them singing a Mandarine cover of "Shake it" by SISTAR where the girls even twerked on Chinese national TV in front of members from the Chiense sister group of AKB48)
Korea: 4CARAT, they have been a girlgroup of 4, later 3 girls, no idea if they are still active, who debuted around 2018 an had been 7 years old at debut
Japan: Nono-chan is a curently 6 year old soloist who was 5 years old at her debut
USA: Michael Jackson was 5 years old when he debuted with his siblings back when they used to be a group called "The Jackson Fives"
Germany: The 12 year old singer LIL M, he debuted when he was around 8 or 9 years old
Who's the youngest you know for other countries or is there anyone even younger you know from the already named countries?
