Sum Skyscrapers

It’s my birthday! Here’s two Sum Skyscrapers: one in European day/month/year format, and the other in American year/month/day format. They’re not wildly different, I just couldn’t decide which one to use.

Sum Skyscrapers 1

Sum Skyscrapers 2


  • Standard Skyscrapers rules.
  • However, the clues give the sum – not the amount – of visible numbers.

Corrupt Sudoku

I haven’t seen this variant before, so I took the liberty of naming it. I wouldn’t be surprised if someone else had already invented it, though.

Corrupt Sudoku 1


  • Unlike regular Sudoku, numbers do repeat in rows, columns and regions.
  • Each row contains exactly one number twice, but the doubled number is different in each row.
  • Also, each row is missing exactly one number, but the missing number is different in each row.
  • The same applies to columns and regions.

For an easier puzzle, change the 5 in the top row into a 1. It’s not that hard, but getting used to the logic probably makes it harder.

EDIT: Corrected the rules. The old rules weren’t strict enough to guarantee an unique solution.