So called semi-underground spaces in Seoul city emerged in the 1970s as subterranean air-raid shelters. As the population grew, the spaces transformed into illegal housing. One of the visible characteristics of the spaces is small eye-level windows that admit very little light into the interiors. The project suggests how daylight to the interior spaces by day and the artificial light extending to the narrow roads by night can be amplified. The jury found the project very viable. It takes its starting point in a realistic situation and a real challenge, and subsequently suggests a solution that seems realisable as a very simple intervention of the cubic, sliding window prism. The project is illustrated in a very beautiful way and the presentation of the main idea and the use of the sliding prism is truly convincing. For the jury, it is a clear winner in the category for Asia and Oceania.