The Mujigae or Rainbow Rock of Sea Chilbo is standing on the seashore in Pochon-ri, Myongchon County, North Hamgyong Province of Korea.

The rock seems suspended in the air with one end rooted on the slope of mountain and the other in the sea. It looks like a rainbow. It is called Mujigae Rock of Sea Chilbo as it is standing in Sea Chilbo, one of the tourist attractions of Mt. Chilbo, a celebrated mountain of Korea.

The rock was formed as a result of elevation accompanied by erosion of the sea after basalt covered sandstone and conglomerate.

The queer rock has long been known as a scenic beauty along with the Kangson or Fairies-Descending Gate, Sol or Pine Islet and Tal or Moon Gate in the area of Sea Chilbo.

It seems more beautiful as the pine, oak, maple and other trees growing on the low hill in the west are in good harmony with the yellowish igneous rocks around.

When waves hit the rock in the luniform hollow, splashing fog, the Mujigae Rock seems to be hung on the clouds. The Mujigae Rock of Sea Chilbo is a natural monument of academic and decorative significance as it shows the course of its formation and the upheaval of the crust of the earth.