Logic Masters Deutschland e.V.

Normal sudoku rules apply. Don't make any guesses; only fill in numbers you can logically deduce.
Eventually, you will be left with 31 ambiguous cells that could contain multiple numbers.
Shading these cells (yellow) will reveal an image!

I got some comments asking for help calculating the solution code. This is the first puzzle I have uploaded here, so it's also a fun learning experience for me! To make it more clear how the Ambidoku rules work, and how to calculate the solution code, I made a small example: https://tinyurl.com/2t4cf55f

(Click the image to open in SudokuPad)

Or go to https://sudokupad.app/ttctbjc1fq

This is the first puzzle in a series of 3 ambidoku puzzles (uploaded to logic-masters.de).
This first one only requires some basic sudoku-solving strategies and serves to introduce the concept of ambidoku!
When you are done solving the puzzle, save your solution because a secret is hidden across the 3 puzzles. The second puzzle can be found at: https://logic-masters.de/Raetselportal/Raetsel/zeigen.php?id=000K3L