Happy 51st
- Killer cages
- Kropki dots
- Thermometers
- Palindromes
The brief
Normal sudoku rules apply. The grey line ("5") is a palindrome that reads the same in both directions. Digits along the thermometer ("1") must increase from the bulb end. Digits in cages sum to 13; negative constraint applies -- no unmarked dominoes sum to 13. Digits separated by a white dot differ by 1 (not all dots are shown).