Inkoku: Sudoku Zen In testing

Grind the ink, unroll the paper, and let the numbers settle. Inkoku is a sudoku puzzle painted in the quiet style of Japanese sumi-e: black ink on warm rice paper, a red seal, a drift of cherry petals - and a hanging scroll that paints itself as you solve.

A SCROLL THAT GROWS WITH YOU

Every puzzle you finish in the Journey lays new brush strokes on a painting: a raked stone garden, a koi pond under blossom, bamboo in mist, a temple above the clouds, a maple bridge, a tea house in snow, the moon on still water, Mount Fuji at dawn. Eight chapters, thirty puzzles each, and every finished painting is framed in your Gallery.

CLASSIC SUDOKU, RATED BY THE WAY YOU THINK

Five levels - Easy, Medium, Hard, Expert and Master - graded by the logic each grid really needs, from hidden singles and pointing pairs to X-Wing, Swordfish and long chains, not just by how many numbers are given. Every puzzle has exactly one answer and can be solved without guessing. More than ten thousand verified puzzles are ready offline.

KILLER SUDOKU

After your first ten solves, a second mode opens: dashed ink cages whose digits must add up to their sums. Four levels, from friendly cages to big ones that ask for the rule of 45.

A HINT THAT TEACHES

Stuck? A hint finds the next logical step, names the technique, explains it in one line and marks the cells that prove it. A built-in technique guide covers everything from singles to chains - a calm way to grow your brain games skills.

DAILY CHALLENGE

A new puzzle every day, a calendar of brush marks, a streak to keep, and a gold-mounted scroll for every month you complete.

MADE FOR FOCUS

- Pencil notes, auto notes, eraser and unlimited undo
- Same-digit and row / column / box highlighting, conflict marks
- Number pad that counts what is left and fades finished digits
- Mistake limit with one second chance, or switch it off
- Optional timer, a flow bonus for quick correct digits, and enso circles for clean solves
- Large numbers, a still-background option and an ink-night theme with charcoal paper
- Koto and bamboo-flute music, soft brush and wood sounds
- Statistics for every level: best and average times, streaks, perfect games

Inkoku is free and supported by ads. There are no purchases. No account, no sign-in: your progress stays on your phone.

Breathe in. Pick a cell. Place one digit. That is the whole practice.