How to Play Sudoku (Number Place)

SUDOKU-WEB Guide

This guide explains the three basic operations: number entry, notes, and erasing.

1. Number entry (confirmed numbers)
   • Step 1: Check mode: Ensure "Notes" mode is off.
   • Step 2: Select a square: Click or tap the empty square.
   • Step 3: Enter number: Press 1-9 buttons to fill the square.
2. Adding notes (candidate numbers)
   • Step 1: Toggle Notes: Click the "Notes" button to turn it on.
   • Step 2: Select a square: Click the square to add a note.
   • Step 3: Enter note: Press 1-9 buttons to add small numbers as candidates.
3. Erasing numbers or notes
   • Method A: Same number: Select the square and press the same number to erase it.
   • Method B: Eraser: Select the square and press the "Eraser" button to clear all numbers/notes.

   Combine these operations to solve puzzles efficiently.

Rules

• Board: 9x9 squares, divided into nine 3x3 blocks.
• Numbers: Use numbers 1 to 9.
• Filling: Place numbers in empty squares without repeating in row, column, or block.
• Prohibited: No duplicates in row, column, or 3x3 block.

Basic solving tips

• Eliminate impossible candidates by checking rows, columns, and blocks.
• Fill squares with a single candidate first.
• Use notes to organize possibilities.

Keep in mind: Do not repeat the same number in the same row, column, or block.