One Line: Number Path Puzzle

One line. Every square.
A calm, surprisingly deep path puzzle: trace the numbers in order — 1, 2, 3 — and fill the whole grid with a single stroke.
A fresh daily puzzle turns spare minutes into the perfect little brain break.

■ How to play
• Start your line at 1
• Pass the numbers in order: 1 → 2 → 3 …
• Visit every open square exactly once (dark blocks are walls)
• Finish on the last number. Drag back to erase, or touch any point on your line to redraw from there

■ Why you'll like it
• Always fair: every board is checked by a solver, so there is exactly one solution — no guessing
• Endless boards: puzzles are generated on your device and prepared in advance, so there's no waiting
• Daily puzzle: the same board for everyone each day — build your streak
• Four difficulties: gentle 6×6, 7×7, hard 8×8 and a fiendish 8×8
• Ranks: climb from Novice to Grandmaster; harder boards count for more
• Progress: clears, streaks, best times and no-hint rate
• Dark mode, in English and Japanese

■ Made for you if…
• You want a quick, satisfying "solved!" on a commute or coffee break
• You love logic puzzles but dislike ambiguous ones
• You'd like a small daily habit that keeps your mind moving
• You prefer a clean, quiet, grown-up design

■ Good to know
• Free to start. No subscriptions
• No third-party ads
• Your records stay on your device

■ Privacy
• No account or sign-in
• Puzzles are generated and played offline
• The only network use is reading public App Store information to show other apps from the same developer
• No tracking