Killer Sudoku User Guide

Welcome to the Killer Sudoku game! This enhanced version of Sudoku adds a mathematical twist to the classic puzzle. Instead of starting with pre-filled numbers, you’ll use “cages” with sum targets to solve the puzzle.

Game Objective

Fill the 9×9 grid with numbers 1-9 following these rules:

1. Each row must contain all digits 1-9 without repetition

2. Each column must contain all digits 1-9 without repetition

3. Each 3×3 box must contain all digits 1-9 without repetition

4. The sum of numbers in each cage must equal the cage’s target number

5. Numbers within a single cage must be unique

Game Elements

1. Sudoku Board

• The 9×9 grid divided into rows, columns, and 3×3 boxes

• Each cell can contain a number from 1-9

• Dashed borders outline “cages” with sum targets

2. Cages

• Groups of cells outlined with dashed red borders

• Each cage has a target sum shown in the top-left corner of its first cell

• All numbers in a cage must add up to this target sum

• Numbers in a cage must be unique (no duplicates)

3. Controls Panel

Timer

• Shows elapsed time since starting

• Click to pause/resume the timer

• Timer format: MM:SS

Mistakes Counter

• Shows how many errors you’ve made (0/3)

• Turns red when you have 1 mistake remaining

• Game ends after 3 mistakes

Difficulty Selector

• Choose from 4 difficulty levels:

  • Easy: 28 cages

  • Medium: 32 cages (default)

  • Hard: 36 cages

  • Expert: 40 cages

• Higher difficulty = more cages = more complex sums

Hints Counter

• Shows available hints (3/3)

• Each hint reveals the correct number for a selected cell

• Hints are limited to 3 per game

4. Stats Panel

• Cages: Number of cages in current puzzle

• Total Sum: Always 405 (sum of 1-9 in each row/column/box)

• Difficulty: Current difficulty level

5. Virtual Keyboard

• Click number keys (1-9) to fill selected cell

• Delete button clears the selected cell

• Keys turn gray when number conflicts with Sudoku rules

6. Toolbar

New Game

• Starts a fresh puzzle at current difficulty

• Resets timer and mistake counter

Hint

• Reveals the correct number for selected cell

• Limited to 3 hints per game

Download PDF

• (Placeholder function) Would generate a printable puzzle

How to Play

1. Select a cell by clicking on it

   • Selected cells turn light blue

   • Related cells (same row/column/box) are highlighted

2. Enter a number using:

   • Virtual keyboard

   • Number keys (1-9) on physical keyboard

   • Delete/Backspace to clear a cell

3. Follow the rules:

   • No duplicate numbers in rows, columns, or 3×3 boxes

   • Cage numbers must sum to target and be unique

   • Use the “Rule of 45”: Each row/column/box sums to 45

4. Use hints strategically:

   • Each hint reveals one correct number

   • Only 3 hints available per game

   • Select an empty cell before using a hint

5. Avoid mistakes:

   • Incorrect entries turn red and shake

   • After 3 mistakes, game ends

   • Correct entries appear in dark blue

Winning the Game

Complete the entire grid correctly to win! You’ll see a congratulatory message with your:

• Completion time

• Number of mistakes

• Hints used

• Difficulty level

Tips & Strategies

1. Start with small cages – they have fewer number combinations

2. Look for cages that cross multiple 3×3 boxes

3. Use the Rule of 45 to find missing numbers in rows/columns

4. Focus on cages with unique sum combinations

5. Use highlighting to see conflicts before entering numbers

Enjoy the challenge of Killer Sudoku!