How to Solve Medium Sudoku: Moving Beyond the Basics
Once you've mastered basic singles, the next plateau in your solving journey requires medium Sudoku strategies. At this intermediate stage, finding the final answer directly becomes harder. Instead, you must learn to work with groups of candidates to logically eliminate possibilities.
The Power of Pencil Marks and Elimination
What makes a strategy "Medium"? While easy techniques rely on scanning a single cell or line, intermediate strategies require you to look at multiple cells simultaneously and find logical relationships between them.
To use these techniques effectively, you will usually need to start using pencil marks (writing down all possible numbers for empty cells). Instead of asking, "What number goes here?", your goal shifts to asking, "Which cells can I safely eliminate this candidate from?"
Core Intermediate Techniques to Master
If you are stuck on a newspaper-level puzzle, applying these logic patterns will help you break through:
- Pairs and Triples: Strategies like the Naked Pair, Hidden Pair, and Naked Triple involve finding sets of numbers restricted to a specific number of cells. This allows you to cross those candidates off elsewhere in the block, row, or column.
- Intersections (Pointing Pairs & Box/Line Reduction): These techniques focus on how candidates in a 3x3 box align with a specific row or column to rule out numbers in adjacent areas.
Mastering these medium-difficulty techniques is essential for solving most standard puzzles. Once these feel like second nature, you'll be ready to tackle Hard Sudoku Strategies.
Frequently Asked Questions About Intermediate Sudoku
What is the most common medium Sudoku strategy?
The Naked Pair is arguably the most common intermediate technique. It happens when two empty cells in the same row, column, or 3x3 block contain the exact same two candidates. Because those two numbers must belong to those two cells, you can safely erase them as candidates from any other cell in that unit.
Do I need to write down candidates to solve medium puzzles?
Yes, solving medium Sudoku puzzles almost always requires using pencil marks (noting candidates). Intermediate logic relies on seeing patterns between possibilities - such as pairs or intersections - which is very difficult to track purely in your head.
Why am I stuck on a medium Sudoku puzzle?
If basic single strategies aren't working, you have likely missed a pair or an intersection. First, ensure you have filled in all pencil marks. Then, carefully scan each 3x3 box to see if certain numbers are restricted to a single row or column, which will point you toward your next elimination.