Logic Masters Deutschland e.V.

RULES:

Normal Sudoku Rules Apply

Column 9 is filled with ocean and the blue line represents a seawall. The wall has breached at exactly one place between two cells (to be determined by the solver), and the ocean is flooding the city. Tiles flood according to the following rules: Any digit X or lower (X to be determined by the solver) that is orthogonally adjacent to another flooded cell or the breach in the seawall becomes ocean. No 2x2 area is entirely ocean (including column 9), and the flooding (i.e. ocean outside of column 9) will reach every marked 3x3 box. Every non-ocean tile is part of an orthogonally connected chain of non-ocean tiles that touches an edge of the grid.