This study (in Dutch) shows the current (2016) state of the urban courtyards in a specific area (Bellamy neighborhood) of Amsterdam, the Netherlands. One of the observations is that these urban courtyards have become 25% extra 'stoned' (build, paved, etc.) in only ten years time, from 37% stoned (2005) unto 56% stoned (2015). At the same time, watermanagement problems are getting bigger and bigger in urban city-centers, especially drainage is overflowing when it rains. It is not imaginary that these urban courtyards will further be 'stoned' up until 75% if no action is taken. The report concludes wit a set of 50 possibilities ('50 shades of green') to re-green these urban inner courtyards and calls for action of the urban policy makers (Amsterdam City Board).