Logic Masters Deutschland e.V.

The puzzle :

Play on Penpa (answer check with green lines for the U-Bahn).

Rules :

Yin Yang : shade some cells such that all shaded cells are orthogonally connected, all unshaded cells are orthogonally connected, and no 2x2 area is fully shaded or fully unshaded.

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

Interaction : For each row/column, the set of clues outside the grid is given either for the shaded cells or for the unshaded cells. It cannot be fully true for both. A clue 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.

Clues are encrypted. Each distinct letter represents some unique number from 0-12. The letters A and T are naughty. They may each replace 2 different numbers, if needed. For each occurence of A or T in the clues, the clue has the value of one of these numbers, to be determined by the solver.

R11c11 (marked with a 1 cell cage) cannot be empty, ie it has to contain a U-Bahn shape.

Note : the cells marked with dotted edges at the top and left of the puzzle are here to help you keep track of the shading of each set of clues.

Example puzzle:

Play on Penpa (answer check with green lines for the U-Bahn).

Note : the corner pencil marks are not needed for the solve or answer check. They are a way of notating that I use while solving this kind of puzzle, and it is useful here to keep track of the sums.