Naked Single
One cell has only one legal candidate. Place it.
SUDOKU ACADEMY
Learn the move.
Then recognise it yourself.
The in-game Academy turns technique knowledge into guided practice and mastery. This public guide gives you the map.
Hidden Single
A digit can appear in only one cell within a row, column or box.
Locked Candidates
A candidate confined to one line inside a box can be removed from the rest of that line.
Naked Pair
Two cells share exactly the same two candidates, locking those values there.
Hidden Pair
Two digits can occur only in the same two cells of a unit.
Naked Triple
Three cells collectively contain only three candidates, eliminating them elsewhere in the unit.
X-Wing
A rectangle formed by two rows and two columns can eliminate a candidate from aligned cells.
Coach uses progressive disclosure.
Inside a live Classic puzzle, Coach moves through five levels: Nudge → Focus → Technique → Explain → Apply. You decide how much help you want before the answer is touched.