Why are Korea and Japan rivals?

https://www.quora.com/Why-are-Korea-and-Japan-rivals/answer/%E6%A1%91%E7%94%B0-%E5%81%A5%E5%8F%B8-Kuwata-Kenji?prompt_topic_bio=1

It seems that there is a misunderstanding.
The Japanese-Japanese way of thinking has not changed since 1885.
https://www.youtube.com/watch?time_continue=1&v=z_v5r_4xxHQ