Logic Masters Deutschland e.V.

Previous Dutch Flat Mate Puzzles
This has been a weekly series since '18 Oct 23'. Here is a spreadsheet link for all the previous puzzles in the series, which also has a few teasers for upcoming constraints/guest setters in the series (subject to change).

This alternative link offers a limited LMD search for Dutch Flat Mates.

To play the puzzle, please click the image:

Puzzle Link

Initial Setter Difficulty: 2.5-3 / 5

Normal Sudoku rules apply
Place the digits 1-9 so that they do not repeat in any row, column, or 3x3 box.

Dutch Flats
Every 5 in the grid must have a '1' directly above it or a '9' directly below it. It may have both, but it doesn't need both.

A-Sums
Clues outside the grid indicate the sum of the digits placed before Digit A in the respective row or column. Digit A is constant throughout the entire puzzle. For clarity - It is part of solving to find the value of A, and Digit A is not included in the sum.

Hint to start

You can soon limit the locations and value of Digit A, by how many digits must be included/excluded from the sums... and then we Flat Mate! :)

Example A-Sums puzzle, please click the image:

Example Link

Example puzzle solution path summarised

The 9 clue is 2+3+4 (in some order), Digit A is 1, placing 1 in Row 3
As 1 is unavailable, the 5 clue is 2+3 (in some order), placing 1 in Row 2
As 1 is unavailable, the 6 clue is 2+4 (in some order), placing 1 in Row 4
Classic Sudoku resolves the grid.

Special Thanks
Thank you again to Marty_Sears for my official birthday Dutch Flat Mate, and thank you for all the comments wishing me well, and the setters that gifted me 'bootleg' flat mate puzzles! It was a lot of fun to solve them all!

This constraint was brought to my attention by this Richard puzzle, and his puzzle page contains further credit history.

Next Week
Next week we welcome the return of Crusader175, with Y-Sums! Crusader175 has used Y-Sums before, including within this great puzzle if you would like some homework ahead of next week.