Logic Masters Deutschland e.V.

Normal sudoku rules apply.

Divide the grid into islands of one or more orthogonally connected cells such that each island contains a set of digits summing to 9. Digits may repeat on an island but each island must contain a unique set of digits.
Islands must not touch each other (even diagonally) except at cells joined by a line, each line marks a bridge between two islands.
All cells not part of an island are in the ocean which must be a contiguous region of orthogonally connected cells that never completely fills a 2x2 area.

A digit in a circle counts the number of cells in its own region (island or ocean) seen in its row and column combined, including itself, where cells in other regions block vision and are not seen.

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