Logic Masters Deutschland e.V.

Normal Sudoku rules apply. The clues outside the grid give the length of the longest ascending subsequence of digits in that direction. A subset of the digits 1-9 is called "ascending subsequence" of a row/column, iff the order in which it appears in that row/column coincides with its usual ordering.

For example: A row which reads (from the left) 342156987 has three ascending subsequences of length 5, namely 34569, 34568 and 34567 as well as many shorter ones. But since there is no longer one, it could only have a 5-clue on its left. Similarly, if read from the right, the same row has three ascending subsequences of length 3 (789, 124, 123), but no longer ones, so it could have a 3-clue to its right.

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Enjoy! :^)