Suzuka Nakamoto performing in 2010 with ASH (Hiroshima actors school)

Sayashi Riho, is leaving her idol group Morning Musume at the end of the year.

Her and Su-Metal used to compete for the top spot during the ASH (Hiroshima actors school) days.

This entertainment trivia, hits home to Su fans. That footage is a piece of the past the connects the two performing together, perusing their dreams.
Now before one gets the wrong impression, Sayashi wants to study abroad, pursue dancing and learn English. She is just taking a different step in her growth.

Thank to monsterpanda for explaining

2010/03/14 ASH発表会 Bクラス曲

So Jason Becker dig BABYMETAL!
BABYMETAL live at DiverCity Tokyo 2013 (video)