Killer Sudoku vs Sudoku: which should you play?

What stays the same

Both end the same way. Every row holds 1 to 9 once, every column holds 1 to 9 once, and every three by three box holds 1 to 9 once. Both have exactly one solution, and neither needs a guess.

If you can finish a Sudoku you already have the machinery for Killer. Nothing you learned goes to waste.

What changes

• Sudoku hands you given numbers. Killer hands you cages, which are groups of squares with a total.
• A cage never repeats a digit, so a total plus a cage size often pins the possible numbers down to one combination.
• Killer rewards arithmetic you can do in your head. A two square cage totalling 17 can only be 8 and 9.
• Sudoku rewards scanning. You look for where a number can and cannot go, over and over.

Which is harder

Killer looks harder and often starts harder, because an empty grid gives you nowhere obvious to begin. Once you know a handful of cage combinations that feeling goes away, and a medium Killer is roughly a medium Sudoku with extra signposts.

The honest answer is that difficulty comes from the puzzle, not the type. A hard Sudoku with eighteen givens will beat a gentle Killer every time.

Which should you play

Play Sudoku when you want something you can pick up and put down, where every move is a small piece of scanning.

Play Killer when you want a puzzle that fights back at the start and then opens up. The moment the first few cages resolve is the best feeling either game offers.