Renzoku — Nikoli sum-line logic puzzle: fill every cell with a digit 1..N such that each orthogonally connected run of same-digit cells has exactly that many cells. 30 levels across 5 tiers from 4x4 Beginner to 7x7 Expert.
RENZOKU
Sum Line · Nikoli logic puzzle
How to Play
•Fill every cell with a digit 1 to N (where N is the grid size).
•Run rule: if two same-digit cells are orthogonally adjacent, they belong to the same run, and that run must contain exactly that many cells.
•Two runs of the same digit may not touch each other (or they'd merge into a longer run).
•Every puzzle has a unique solution.
Why Renzoku?
Renzoku (連珠, “continuous pearls”) is a 1998 Nikoli invention. Each cell carries a digit; the puzzle is solved when every orthogonally connected group of equal digits forms a run whose length matches the digit.
It sounds simple but the cascading constraints create satisfying logic chains: an isolated 1 is a singleton, a run of 3s needs exactly 3 cells, and the bigger the run, the fewer cells it can touch.
30 hand-crafted levels across 5 tiers from 4×4 Beginner to 7×7 Expert.
Choose Level
0 / 30 solved
Level 1
Beginner · 5×5
⏱0:00
💡3
Digit
Erase
Tap a white cell, then tap a digit below to fill it. Tap a digit twice to remove.
Solved!
★★★
Beautiful logic work!
Settings
Music
Ambient chord progression
Sound Effects
Click, hint, win
Auto-check
Highlight errors as you play
How to Play Renzoku
Setup. The grid is N×N. You must fill every cell with a digit from 1 to N.
The Run Rule. Whenever two same-digit cells are orthogonally adjacent, they form a single connected run. The run must contain exactly that many cells — so a run of three 3s is exactly three orthogonally connected cells, a run of two 2s is exactly two adjacent cells, etc.
No merge. Two separate runs of the same digit must not touch (otherwise they would merge into a longer invalid run).
Strategy. Look for 1s first — they must be isolated, so wherever a 1 is given, its 4 neighbors cannot be 1s. Look for the biggest digit N — the run of N must use exactly N cells (often half the grid), which heavily constrains the remaining cells.
• Digit mode: tap a cell, then tap a digit on the keypad.
• Erase mode: tap any filled cell to clear it.
• Check: validates your current state. Errors are highlighted.
• Hint: reveals one correct cell. You have 3 per level.
• Clear: removes all your entries.
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