Sudoku hints that explain the logic, not just the digit

Standard Sudoku hints simply fill a random or selected empty cell with its final answer, which solves that square without teaching you why. Step-by-step logic hints inspect your current board, choose the simplest available deduction, highlight the exact rows, columns, boxes or cages involved, and explain the rule before placing or eliminating a candidate.

Every Sudoku player eventually hits a wall: the easy singles are gone, every remaining empty cell has two or three candidates, and five minutes of scanning turns up nothing. What happens when you tap the Hint button determines whether you actually get better at Sudoku or stay stuck at the same difficulty level forever.

Answer-reveal hints vs. step-by-step teaching hints

There are two fundamentally different ways a Sudoku app can implement hints:

Feature	Answer-Reveal Hints (Lookup)	Step-by-Step Logic Hints (Teaching)
How it works	Reads the pre-computed solution for one cell	Runs a human-style deduction engine on your current grid
What it shows	Drops the final digit into the cell immediately	Names the technique and walks through 2–4 visual steps
Candidate eliminations	Cannot explain intermediate candidate removals	Highlights locked sets, wings, fishes and cage rules
Effect on learning	Zero — you still do not know why that digit belonged there	High — teaches you to spot the same pattern next time
Killer Sudoku support	Reveals a number without mentioning cage math	Explains Rule of 45 and unique cage combinations

How a teaching hint breaks down a move

A human solver never jumps straight to an answer on a Hard or Expert board; they narrow down possibilities first. Skudo's hint engine mirrors that exact process across 34 named Classic and Killer techniques.

Instead of dumping a paragraph of dense text, each hint unfolds as a short sequence of visual steps right on your board:

Identify the pattern and name the technique: Whether the simplest available move is a Hidden Single, a Naked Pair, a Swordfish or an XY-Wing, the hint header tells you what you are looking for.
Highlight the relevant units and cells: The board dims unrelated squares and highlights the exact row, column, 3×3 box or Killer cage that forms the deduction.
Show the elimination or placement: Before changing the grid, the hint shows which candidates are ruled out—and why—so you can verify the logic with your own eyes.

Why ordering techniques from simplest to hardest matters

A common frustration with automated solvers is that they sometimes point out an exotic chain when a simple Locked Candidates elimination was sitting in Box 1.

Skudo's hint ladder always searches from the lowest rung upward:

Level 1 (Singles): Naked Single and Hidden Single.
Level 2 (Intersections & Locked Sets): Locked Candidates (Pointing & Claiming), Naked Pair, Hidden Pair, Triples and Quads.
Level 3 (Fish & Wings): X-Wing, Swordfish, Skyscraper, Two-String Kite, XY-Wing and XYZ-Wing.
Level 4 (Chains & Uniqueness): Unique Rectangle, Remote Pairs, XY-Chain and 3D Medusa.
Killer Sudoku ladder: Rule of 45, Killer Combinations, Innies & Outies and Cage Split.

Because the same engine powers both the in-app hints and the worked solutions on the Daily Sudoku Challenge, every technique it names links directly to a dedicated lesson in our Sudoku technique guides.