How to Use SudokuStreak
SudokuStreak is a feature-rich Sudoku platform that lets you play multiple puzzle variants, track your progress, compete on leaderboards, and improve your solving skills. This guide walks you through everything you need to know.
Starting a Game
When you open the Play page, you will see an empty board with a Start Game button in the centre. The game does not start automatically — you choose when to begin.
- Select your preferred puzzle type (Classic, Killer, X-Sudoku, or Samurai) using the type buttons at the top of the page.
- Choose a difficulty level from the dropdown: Easy, Medium, Hard, Expert, or Evil.
- Click ▶ New Game to generate a fresh puzzle, or click ▶ Start Game on the overlay to begin.
On mobile, the puzzle-type and difficulty selectors appear as dropdowns directly in the bar above the board, and the New Game button is always visible.
The Game Board
The Sudoku grid occupies the centre of the screen. Below the grid you will find the number pad and action buttons. At the top of the board is the stats bar showing your current time, error count, and your live Sparks total (your running score). On wider landscape screens the controls sit to the right of the board; on phones they stack neatly below it.
Selecting a Cell
Click or tap any empty cell to select it. The selected cell is highlighted with a blue outline. All cells in the same row, column, and 3×3 box are highlighted in light blue so you can see where each number already exists. All cells containing the same digit as your selection are also highlighted.
Entering a Number
With a cell selected, enter a number by:
- Clicking a button on the on-screen number pad (1–9)
- Pressing a number key on your keyboard
If you enter a number that conflicts with the puzzle's solution, the cell turns red and your error count increases. Errors are permanent — each one shrinks your combo bonus (never the base), so a mistake-free game scores higher. See Sparks & scoring below.
Erasing a Number
Select the cell you want to clear and:
- Click the ✕ Erase button
- Press Delete or Backspace on your keyboard
Controls & Buttons
| Button | What it does |
|---|---|
| ⏸ Pause | Pauses the timer and blurs the grid so nobody sees your progress. Click ▶ to resume. |
| Hint | Reveals the correct value for one empty cell. Each hint increases your hint count and reduces your score. You have a limited number of hints per game depending on difficulty. |
| ↶ Undo | Takes back your last entry, restoring that cell to its previous state. Undo affects only the cell — it never changes your errors, hints, jokers or Sparks. |
| ✕ Erase | Clears the selected cell. |
| Notes | Toggles pencil mode. In pencil mode, numbers are written as small candidate notes instead of final values. Notes in a cell are cleared automatically once you place a final digit there. |
| Jokers | One-use power-ups (Reveal Row, Freeze Timer, Solve Box). On desktop they sit in the right-hand sidebar; on mobile, below the number pad (available to registered players) — see the Jokers section below. |
Made a slip? Use Undo (↶ or Ctrl+Z) to take the last entry back out. Undo restores only the cell — an error that was already counted stays counted, and your hints, jokers and Sparks are untouched.
Keyboard Shortcuts
| Key | Action |
|---|---|
| 1 – 9 | Enter the number into the selected cell |
| Delete / Backspace | Erase the selected cell |
| Ctrl + Z | Undo your last entry (cell only — errors, hints and Sparks are unaffected) |
| Arrow keys | Move selection to an adjacent cell |
| P | Toggle pencil / notes mode |
⚡ Sparks & scoring
Your score is shown live as Sparks while you play. It builds up from 0 as you place correct numbers — it never starts high and ticks down. When you finish, the score is:
base × your progress × (1 + combo bonus + time bonus) × type multiplier
- Base & progress — each difficulty has a base value (harder = more Sparks). Your live Sparks climb from 0 toward that base as the grid fills with correct numbers. Cells you reveal with a Hint don't earn Sparks.
- Combo bonus (up to +50%) — a clean run earns the full bonus. Every error or hint shrinks it, but it never takes your score below the base.
- Time bonus (up to +50%) — applied when you finish: beat the normal time and you earn extra, proportional to how much faster you were. Finishing slower than normal costs nothing — there is no time penalty.
- Type multiplier — variants are worth more (for example Samurai ×2). The total never drops below 0.
So the highest scores come from a clean, hint-free solve finished under the normal time. Your Sparks add up across all your games into your total on the leaderboard.
Game Progress & Refresh
SudokuStreak automatically saves your progress to your browser's local storage as you play. If you close the tab or refresh the page, you will see a "Continue your game" overlay showing how much time has elapsed. Click Resume to continue exactly where you left off.
If you want to start fresh instead, click ▶ New Game and confirm the abandon dialog. Note that abandoning a game counts as a loss and is recorded in your statistics.
Daily Challenge
Every day a new puzzle is generated for all players, in three difficulties (Easy, Medium, Hard). Go to Daily Challenge in the navigation to play today's puzzles. Everyone plays the same daily puzzles, so you can compare your times — and completing one keeps your streak going.
Below today's puzzles is a calendar archive. Browse to previous months and replay any day you missed — each day shows, per difficulty, whether you have already played it and your best time. This lets you fill in your history and chase the monthly achievements.
Completing the daily challenge extends your streak counter. Keep playing every day to build your longest streak!
Leaderboard
The leaderboard ranks registered players. Use the tabs to switch between Sparks (your total score), Longest Streak and Games Won. It lists the top 300 players — and if you're outside the top, your own rank is still shown in a separate card, so you always know where you stand.
The leaderboard ranks registered players. You can still play and earn Sparks without an account — pick a name and avatar and start solving — and when you create an account your Sparks total carries over, so you can claim your place on the leaderboard under your own name.
Achievements
Achievements are unlocked automatically as you play. They are awarded for milestones such as completing your first game, maintaining a streak, finishing a puzzle without hints or errors, and mastering every game type. Each achievement is shown as a coloured badge medallion — its tier (bronze, silver, gold, platinum, diamond) reflects how hard it was to earn. Check your achievements on your Profile page, where you can also share any badge.
Some examples of achievements you can earn:
- First Step — Complete your first game
- No Help Needed — Finish a game without using any hints
- Perfect Game — Finish with zero hints and zero errors
- Week Warrior — Maintain a 7-day daily challenge streak
- Speed Solver — Complete an Easy puzzle in under 3 minutes
- Evil Slayer — Complete an Evil difficulty puzzle
Monthly daily badges: play every day of a calendar month on a given difficulty to earn that month's badge — finish all three difficulties for a full-month bonus. The calendar archive on the Daily Challenge page makes it easy to mop up any days you missed.
Coins & Shop
You earn coins by completing games — the more Sparks you score, the more coins you get (about 1 coin for every 45 Sparks). Coins can be spent in the Shop on hint packs and special power-ups called Jokers. Coins, the Shop and Jokers are available once you create a free account — anonymous play earns Sparks only.
Jokers
Jokers are one-use power-ups that give you a boost during a game. Three types are available:
- Reveal Row — Fills in all correct values in the row of your selected cell.
- Freeze Timer — Stops the timer for 60 seconds, giving you extra time without penalty.
- Solve Box — Automatically fills the correct 3×3 box containing your selected cell.
Jokers are bought in the Shop with coins (you may also receive one during the tutorial). Use them wisely — each is consumed immediately when activated.
Profile & Statistics
Your Profile page shows detailed statistics: total games played, completed, best times per difficulty, average time, and your current and longest streaks. All achievements you have unlocked are displayed with their badges.
You can also change your display name on the profile page (subject to a 30-day cooldown between changes).