Singer Yu Hee-yeol's alleged plagiarism surfaced again. He just apologized for the "similarity" with Ryuichi Sakamoto's song. This time, it is suspected that Sung Si Kyung's "Happy Birthday to You" released in 2002 and Koji Tamaki's masterpiece released in 1998 are similar. The lyrics, composition, and arrangement of Sung Si Kyung's songs are by Yu Hee-yeol. .. ..