North Korea conducted their sixth nuclear test on Sunday, this time of a significantly more powerful weapon believed to be a two-stage, or hydrogen bomb.

Because North Korea has conducted all of its nuclear testing, Sunday’s included, underground in their Punggye-ri complex, details are sparse, but intelligence gathered from seismic readings suggest that Kim’s claims are likely accurate, and that North Korea now possesses the means to produce dramatically more powerful nuclear weapons than ever before; ten times more powerful than their last test, conducted in September of 2016, according to reports from both Japanese and South Korean officials.

According to estimates, Sunday’s test was conducted using a bomb with a yield believed to be 120 kilotons.  As a frame of reference, the bombs dropped on Hiroshima and Nagasaki at the end of WWII were 15 and 20 kilotons respectively.  This advancement indicates that Kim’s nuclear weapons have now graduated into modern-city killers, in terms of destructive power.

“That scale is to the level where anyone can say (it is) a hydrogen bomb test,” said Kune Y. Suh, a nuclear engineering professor at Seoul National University.  “North Korea has effectively established itself as a nuclear state. This is not just a game changer, it’s a game over,” Suh added.