Practise: Hidden Triple
This puzzle is picked so that the easy moves run out and exactly the Hidden Triple gets you going again. Solve as far as you can — when nothing obvious is left, the pattern is waiting for you.
Skip the obvious cells and start right where the technique is needed.
How to spot it
For each digit missing from a unit, list the cells that could take it. Look for three digits whose possible cells all fall inside the same set of three. The digits do not each need all three cells — two of them is enough, as long as no digit escapes the set.
Put it to use
Where you will meet it
Hard grids are built around moves like this one. That is where it earns its keep.
Play HardStuck 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.
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