North Korea has created a new holiday to mark the successful launch of its biggest nuclear-capable missile last year, according to state media, in a move that one expert said may be an attempt to strengthen the legitimacy of Kim Jong Un’s daughter introduced for the first time at the test.

The standing committee of the DPRK’s rubber-stamp parliament “unanimously” approved a decree to establish Nov. 18 as “missile industry day” (미싸일공업절), Korean Central News Agency (KCNA) reported on Sunday.