Logic Masters Deutschland e.V.

If you are unfamiliar with U-Bahn, here is a guide that covers the core logic.

Draw a totally connected loop network through the centers of some unshaded cells, which may branch or turn, but may not have any dead ends.

A clue outside the grid indicates how many times the corresponding line shape (i.e. a cross, branch, straight line, or turn) appears in the corresponding row or column, irrespective of the line shape's rotation.

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Play on Penpa+

Play on SudokuPad