This Sudoku Has No Digits At All!

Phistomefel has produced this, at first sight baffling, killer sudoku - can you find x?! Try the puzzle here:
https://cracking-the-cryptic.web.app/...

Rules:
Normal sudoku rules apply. Digits may not repeat within a cage. There exists a two-digit number x, such that the digits in each cage add up to a multiple of x. The number x is the same for each cage and has to be determined first.

The puzzle appeared on Logic Masters Germany here:
https://logic-masters.de/Raetselporta...

Our upcoming app is called Miracle Sudoku:
https://store.steampowered.com/app/13...

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The solution video for our Sudoku Hunt is also now available for all $3 patrons and above. Congratulations to the 260+ solvers who have completed the hunt correctly!

You can become a patron here:
  / crackingthecryptic  

Joke van Veenendaal's new puzzle hunt is also available free at our patreon page above.

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Our Chess Sudoku App has just been updated to include lots of Queen Sudoku puzzles! Do update your app to access these puzzles :)

Our Sandwich Sudoku App has just been updated to allow users to transfer data between different devices! This update is coming later this month for Classic Sudoku, Chess Sudoku and Thermo Sudoku!

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AppStore: https://apps.apple.com/us/app/thermo-...
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Steam: https://store.steampowered.com/app/13...

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▶TRY OUR CLASSIC SUDOKU APP◀
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▶TRY OUR SANDWICH SUDOKU APP◀
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Steam: https://store.steampowered.com/app/11...
Android: https://play.google.com/store/apps/de...

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▶SOFTWARE◀
Play the puzzle in the video by clicking the link under the video (above). We are building a website which will allow you to enter your own sudoku puzzles into the software and this is coming soon!

▶Logo Design◀
Melvyn Mainini

▶ABOUT US◀
Hi! We're Simon Anthony and Mark Goodliffe, two of the UK's most enthusiastic puzzle solvers. We have both represented the UK at the World Sudoku Championships and the World Puzzle Championships. We're also "cryptic crossword" aficionados. Mark is the twelve-time winner of The Times championship and Simon is the former record holder for most consecutive correct solutions to The Listener crossword. We hope we can help your puzzle solving while also introducing you to some of the world's best puzzles.

Thank you for watching!
Simon and Mark