Practise: Cage combinations
This Killer puzzle stalls at exactly the point where Cage combinations is needed. Work it out yourself, or jump straight to that position.
Skip the obvious cells and start where the technique matters.
Your turn first
Spot the idea before the hint explains it
- 1. Look
- 2. Check
- 3. Proof
Look at the marked starting cell, cage outline and sum. Which digit or combination is forced, and what visible sum fact supports your idea?
How to spot it
Look for the extremes first. Small sums in small cages and large sums in small cages are the most restrictive: 3 in two cells, 4 in two cells, 6 in three cells, or at the other end 17 in two cells and 24 in three cells. These have exactly one possible digit set.
Put it to use
Where you will meet it
Medium grids are where this move starts to matter: the obvious cells run out and the pattern takes over.
Play MediumStuck on a grid of your own?
Type the position into the solver and it walks the whole solution, naming the technique behind every step — including this one.
Open the solver