We already know that Babymetal are the single best thing to happen to metal in the past decade, and we know that the adorable/brutal Japanese girl group’s first-ever world tour has been a huge success so far. But how do those numbers bore out when they’re combined to produce some kind of meaningful metric? In other words, we can easily see that Babymetal’s four-month old video for “Gimme Chocolate” has over 12 million plays on YouTube, but how many of those views came from Japan, where the girls already headline arenas? What meaningful impact has their sudden rise in worldwide profile had on their careers?

Using at least one metric, the Spotify Viral 50 chart, quite an impact indeed. Babymetal performed at the massive Sonisphere festival in Knebworth, then followed that with a headline performance at The Forum in London two days later. So naturally you’d expect that the girls experienced an uptick in Spotify plays, which is exactly the case.

The “Viral 50” chart, unlike the “Spotify 50” — which simply ranks by number of plays — attempts to establish a metric of virality by dividing a song’s streams by the amount of times that song has been shared by users in the last week, producing a ratio, the higher the better. “Gimme Chocolate” and “Megitsune” landed at #8 and #12 on the UK chart this week, the former of which actually jumped down a notch from the week prior (it’s already been two+ weeks since Sonisphere, after all).

I’m curious to see whether Babymetal’s upcoming string of shows with Lady Gaga (plus an LA headline show) has the same effect on their plays in the US. No disrespect to our British friends, but the US offers a much larger listenership than the UK, and I’m sure Babymetal’s handlers are targeting it aggressively, or at least testing the waters. I know you’re waiting with bated breath to find out, so I’ll be sure to post an update!