North Korea has 0 Coronavirus cases?

North Korea claims to have 0 coronavirus cases. China, its primary trading partner and northern neighbor, has 80,422 according to WHO's Situation Report-44. South Korea has 5,328 cases. There was a picture with Kim Jong Un enjoying his artillary display with masked soldiers standing next to him. Why the masks if there is no disease in country and the borders are closed? AP has an article that indicates that there may be widespread disease in North Korea. Nobody knows and nobody can help. Lack of transparency makes the disease worse, that is one of the lessons from this virus.