✨ JUST 3 MINUTES A DAY

Sudoku, but sweeter —
and it doesn't need the internet.

Candoku is a candy-themed Sudoku app with a new puzzle every day. Play anywhere — on a flight, underground, out of signal — no wifi, no login, no pressure.

App Store Google Play Download free — App Store · Google Play

Features

✈️

Play completely offline. No wifi, no account, no connection required — your puzzle is always there, wherever you are.

📅

A new puzzle every day. A short daily challenge that fits into a quiet five minutes, building a streak you can come back to.

💡

Stuck? Tap a hint. A gentle nudge when a board has you stumped, so getting stuck never means giving up.

🎚️

Four difficulty levels, easy to expert. Start gentle or dive straight into a real challenge — see the section below.

Studies and Tips by Cognitive Science

Swap your mindless scrolling for a proven brain habit.

🧠

Just 3 Minutes to a Sharper Mind

You don’t need hours of brain training. Recent studies of over 6,500 adults show that "micro-dosing" puzzles for just 3 minutes a day delivers small but significant boosts to your executive function. Candoku is the perfect daily habit to keep your mind agile.

🌙

A Calmer Wind-Down

Racing thoughts at night? Focusing on a puzzle activates your brain's executive network, which naturally quiets the areas responsible for rumination. Clinical trials show puzzle-solving actively reduces state anxiety.

☕

A Clean Reset for Your Workday

Social media interruptions cost focus. Instead, take a Candoku micro-break. Research shows that engaging in a short, structured puzzle reliably raises vigor and cuts fatigue, giving you a clean energy reset.

🛡️

Think Younger, Stay Sharper

Regular puzzle-solving is linked to lasting cognitive benefits. In large-scale studies, frequent puzzlers tested like people 8 to 10 years younger, actively recruiting the brain's frontoparietal networks.

Why Candoku

Candoku pairs a genuinely offline Sudoku experience with a softer, candy-coated look — no grey grids, no forced connectivity, no clutter. It's free to play today, with four difficulty levels from easy to expert, so it grows with you instead of staying one-note.

How to play Sudoku on CANDOKU

Classic Sudoku logic, redesigned as a playful daily puzzle break.

Pick a puzzle

Start with a quick daily challenge or choose your own level.

Read the board

Look across rows, columns, and blocks to spot missing numbers.

👀 Brain Check: Early-Stage Solving

Active visual scanning recruits the Intraparietal Sulcus (IPS), building visuospatial working memory as you track numbers across the grid.

Use logic, not luck

Place each number by deduction, pattern recognition, and elimination.

Get help when stuck

Use hints to keep learning without breaking the flow.

🧠 Brain Check: Late-Stage Logic

As cognitive load shifts, you practice multi-step heuristic reasoning in the Prefrontal Cortex (PFC), sequencing actions and enforcing rules.

Complete your daily win

Finish the puzzle, build your streak, and come back tomorrow.

⚡ Brain Check: Metacognitive Reward

Evaluating numbers engages error-detection centers, while the ventral striatum provides the dopamine drive that makes solving so satisfying.

From easy to evil — Sudoku for every mood.

Some days call for a gentle warm-up. Others call for a real challenge. Candoku gives you four levels — Easy, Medium, Hard, and Expert — so the puzzle matches however you're feeling, not the other way around.

🌱 Easy

A relaxed start, perfect for a quiet break or if you're newer to Sudoku.

⭐ Medium

A steady, satisfying challenge for your daily habit.

🔥 Hard

For when you want the board to actually push back.

⚡ Expert

The real test. Not for the faint of heart.

Availability

Candoku is available on iPhone, iPad, Android, and tablet.

Common Questions

Everything you need to know about Candoku.

Is Candoku free?

Yes! You can download and start your sweet Sudoku journey completely for free.

Do I need internet?

Nope! Candoku fully supports offline play. It's the perfect travel companion.

Is it just classic Sudoku?

It uses the classic 9x9 logic you love, but wrapped in a vibrant, stress-relieving candy theme!

What difficulty levels does Candoku have?

Four: Easy, Medium, Hard, and Expert — so there's a level for a quiet warm-up and one for a real challenge.

Sudoku, but sweeter — and it doesn't need the internet.