TappyPotato logic puzzles

Number & arithmetic

Ripple Effect — rules and where to play

RIPPLE EFFECT · Ripple / Hamon

Fill each bold room with 1 up to n, where n is the room size. Two identical digits must sit farther apart than the digit itself — an odd rule with real bite.

Origin
2005 · Japan
Difficulty
★★★★★ 3–5 / 5
Time
10–40 min
Grid
8×8 – 16×16
Sites
9

Rules

  1. Each bold room is filled with 1 through n, where n is its cell count.
  2. Any two identical digits must be more than that many cells apart, measured horizontally or vertically.
  3. Distance is measured center to center; room borders do not block it.

How to start

Large digits are the most demanding

A 5 needs at least six cells of clearance, which pushes it to the edges.

Solve the small rooms first

A one-cell room is 1; a two-cell room is 1 and 2.

The spacing rule crosses room borders

This is the most counter-intuitive and most valuable part.

Where players get stuck

  • Remembering the spacing as "at least" rather than "more than".
  • Assuming room borders stop the distance count.

Play Ripple Effect

9 sites
Puzzle PicnicFree

Handmade Nikoli-style grids from a mix of setters, picked rather than dumped, playable in the page.

Open → PuzzleMixFreemium

Gareth Moore's site: Sudoku, then Slitherlink, Nurikabe, Futoshiki, Calcudoku and Hanjie.

Open → pzv.jpFree

A wider puzz.link-style database — more types, cut a bit finer.

Open → Penpa+Free

A fat editor for Japanese types: lots of shapes and marks, and it will ingest a puzz.link.

Open → pzplusFree

A community bank with difficulty and clear counts, browsable without leaving the page.

Open → Naoki InabaFree

Naoki Inaba writes a lot, including types you won't see many other places.

Open → Puzzle Square JPFree

A large Japanese variant archive that moves often, with difficulty marks on the grids.

Open → Grandmaster PuzzlesFree

Thomas Snyder's own handmade Sudoku and variants — world-champion difficulty, not generated filler.

Open → GridPuzzleFree

Dozens of grid logic types in the browser, with progress tracking and dailies.

Open →

Browse All-in-one portals →

Also on multi-type portals

Janko.atFree

Otto Janko's German/English archive: hundreds of playable types, all free.

Open → Puzzle RulesFree

Clean rule pages for dozens of types. Fastest way to learn a grid you haven't seen.

Open → NoqxFree

An ASP solver for 170-plus types. Connectivity puzzles tend to come back quickly.

Open → Nikoli Puzzle SolverFree

Z3 under the hood, 100-plus types, including hex and triangle boards.

Open →

Browse portals →

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About this page
  • Last updated 2026-09-22
  • Source Curated compilation of established puzzle rules and listed third-party play sites
  • Audience Players learning Ripple Effect rules or looking for online sites to play
  • Covers Rules summary, how to start, common pitfalls, and the dedicated play sites listed on this page
  • Does not cover Hosted puzzles, worked solutions, official contest rankings, third-party uptime or pricing guarantees
  • Not advice This page is puzzle reference content only. It does not constitute financial, legal, medical or other professional advice.
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