Looking for a puzzle with Hidden Pair…
Hidden Pair
Solve one puzzle and let the hint show the technique at work. Unlimited hints, mistakes do not end the run.
Looking for a puzzle with Hidden Pair…
Two digits are confined to the same two cells of a unit, which lets you strip every other candidate from those cells.
Take a unit and count, for each missing digit, how many cells could still hold it. If two digits both have exactly two possible cells, and those cells are the same pair, you have a hidden pair.
The conclusion runs the opposite way from a naked pair: you do not clean other cells, you clean these two. Every other candidate in those two cells can be erased, because between them they must supply both digits.
Nothing about the two cells looks special. They may carry five candidates each, sitting in a busy row that you have already scanned twice. The pattern is not in the cells, it is in the counts, and counts are invisible unless you do them deliberately.
The practical habit: when a unit resists, list where each missing digit can go in that unit. Two digits with an identical two-cell footprint is the thing you are looking for.
The unit needs both digits, and each has only these two cells available. Two digits into two cells fills them completely, so no third digit can survive there. Erasing the extra candidates is not a guess about which cell takes which — it holds either way.
After the cleanup, the hidden pair usually becomes a naked pair in the same unit, and the naked pair then eliminates those two digits from the rest of the unit. Finding the hidden one first is what makes the second elimination possible.