Logic Masters Deutschland e.V.

Normal Sudoku rules apply.
Rain Clouds (Radar) Rules. Shade some clouds in the grid. Each cloud occupies a rectangular (possibly square) area of cells of at least 2 rows and of at least 2 columns. Clouds do not touch each other orthogonally. Clouds touch each other diagonally ONLY where a checkerboard marking is given. All checkerboard markings are given. Numbers on the edges of the grid reveal the number of cells occupied by cloud segments in that row or column.
ADDITIONALLY, Numbers on the edge of the grid MAY NOT appear in cloud cells in the corresponding row/column.
Killer Cloud Cages. Some cells in the grid have small values in the top left corner. Clouds must claim at least one of these cells but may claim more. If such a cell is part of a cloud (shaded) then that cell must be part of an orthogonally-connected region (a cage) within the cloud that sums to the given value. All cloud cells must be used by Killer Cloud Cages; cage regions may not overlap. Digits may not repeat in a Cage or in a Cloud overall.
Unused Killer Cage Values exhibit a "negative constraint." If a cell with a value is unshaded, it must not be possible to form an otherwise valid orthogonally connected "cage region" of unshaded cells that sum to the given value. A potential cage may comprise only one cell.