Glass Bead

It was released by Source Music on January 15, 2015, as the lead single of their debut extended play, Season of Glass (2015).

Written and produced by Iggy and Youngbae,[1] the song was described by Fuse as a "nostalgic gem that heavily recalls Girls' Generation's earliest work, from the sound to the energetic choreography".

[2] The song peaked at number 25 on the Gaon Digital Chart and has sold over 1,025,731 downloads, as of July 2016.

[6] In the monthly chart, the song debuted at number 78 for January 2015, with 75,229 downloads sold.

[7][8] In February, the song rose to number 43, with 81,131 downloads sold.