TWICE's Sana is being criticized for expressing her opinion on the end of the Heisei era. 

April 30, 2019, officially marked the last day of the current Japanese imperial era with Emperor Akihito giving up his throne after 30 years and 3 months. 

According to Kotaku, "Traditionally, new eras begin when the current emperor passes away, but Akihito decided to give up the throne, making way for his son’s coronation."

Japanese citizens are expressing bittersweetness at the end of the Heisei era. Sana, a Japanese member of TWICE, also shared she's feeling empty via Instagram and encouraged people to have a good last day of the Heisei era. Her post was written in all Japanese. 

There were some Korean netizens who flooded the post with criticism, stating it's displeasing how Sana, a member of a K-pop group, expressed her personal feelings regarding Japan and written in Japanese on TWICE's official group account. 

They pointed out Sana should be cautious with matters regarding Japan, even if she's Japanese since she's promoting in a K-pop group and Japan-South Korea tensions. 

Comments stated, "It was rude of her to post that," "They have an official Japanese Instagram account too. She should've posted it there. Not liking this at all," "TWICE didn't post anything on Korea's Independence Day. Why is she posting that there in all Japanese?" 

On the other hand, Sana's supporters are stating that she's Japanese and she will obviously acknowledge her own culture.