What is Ripple Effect?

Ripple Effect, also called Hakyuu, is a logic puzzle played on a grid divided into outlined rooms. Each room of N cells must contain every number from 1 through N once, and identical numbers must keep their distance: a number N cannot repeat within N cells in the same row or column. Diagonal repeats are allowed.

What is the spacing rule in Ripple Effect?

The spacing rule says identical numbers must ripple apart. Two equal numbers N need at least N cells between them in the same row or column. So two 1s cannot be adjacent in a line, two 2s need two cells between them, and two 3s need three. The rule only applies along rows and columns, never diagonals.

How do you start a Ripple Effect puzzle?

Begin with the one-cell rooms, which are always 1, then fill the smallest rooms whose limited range forces a value. Each number you place blocks equal numbers along its row and column through the spacing rule, which quickly narrows neighbouring rooms. Work outward from the small rooms toward the larger ones.

Can the same number appear more than once in Ripple Effect?

Yes, across different rooms. The same number can appear many times in the grid, and even twice in one row or column, as long as the two copies are far enough apart to satisfy the spacing rule. What it cannot do is repeat within a single room, since each room holds 1 up to its size exactly once.

Does solving Ripple Effect ever require guessing?

No. A well-made Ripple Effect has exactly one solution reachable by pure logic. Every Puzzle Lair Ripple Effect is generated and verified to be solvable without guessing, so being stuck means there is a deduction you have not spotted yet, often a spacing elimination or a room-and-line crossing you have not run. When you think the grid is complete, press Check to test the board. There is no mistake limit.

Solving guides

From the rulebook

How to Solve Ripple Effect

Ripple Effect, also known as Hakyuu, is a logic puzzle built from outlined rooms. Each room must hold every number from 1 up to its own size, and identical numbers have to keep their distance across rows and columns. Those two rules pull against each other, and once you can read them together they give you plenty to work with. This guide takes you from the rules to the techniques that crack hard grids without guessing.

Play Ripple Effect

The rules of Ripple Effect

A Ripple Effect grid is divided into outlined rooms of different shapes and sizes. A room made of N cells must contain every number from 1 through N exactly once. A one-cell room is always a 1, a two-cell room holds a 1 and a 2, a four-cell room holds 1, 2, 3 and 4, and so on. Unlike Sudoku the rooms vary in size, so the range of numbers a cell can take depends entirely on the room it sits in.

The second rule is the spacing rule, which gives the puzzle its name. Identical numbers must ripple apart: a number N cannot have another N within N cells in the same row or column. So two 1s cannot sit next to each other in a line, two 2s need at least two empty cells between them, and two 3s need at least three. Diagonal repeats are always allowed. Entries give no live feedback as you play, so when you think the grid is complete, press Check to test the board. There is no mistake limit, so you can keep editing or clear the board and start over.

Start with the small rooms

The fastest opening move is filling the forced cells. Every one-cell room is a 1, so write those straight in. Then look at the small rooms next to clues already placed. A two-cell room only holds 1 and 2, so if one of its cells cannot be a 1 because a 1 sits a cell away in the same line, the other cell takes the 1 and this one takes the 2.

Work outward from the smallest rooms. Their narrow range of numbers makes them the easiest place to lock a value, and each number you place starts blocking equal numbers along its row and column through the spacing rule.

Use the spacing rule to eliminate

The spacing rule is your main elimination tool. Whenever you place a number N, sweep along its row and column and rule that same N out of every cell within N steps. A placed 3 forbids another 3 in the three cells to its left, the three to its right, the three above and the three below. Larger numbers reach further, so a high value in a big room clears a wide band around itself.

Run the rule in reverse to force placements too. If a room needs a 2 and only one of its cells is far enough from the other 2s already in those lines, that cell must take the 2. The bigger the number, the longer its reach, so the largest numbers in a room are often the easiest to pin down because so few cells survive the spacing check.

Work the crossings of room and line

Every cell answers to two masters at once: the room it belongs to and the row and column running through it. A cell's candidate list is the set of numbers its room still needs, minus any number blocked by the spacing rule along its lines. When a room has a number left to place and only one cell where the lines do not forbid it, that placement is forced.

Look for cells where a nearly full room crosses a busy line. If a room needs only a 4 and a 5, and the row through one of its cells already has a 4 within range, that cell must be the 5 and its roommate takes the 4. These room-versus-line crossings are where the hardest deductions hide.

Combine room logic with elimination

When the obvious moves run out, write candidate pencil marks driven by both rules. For each empty cell list the numbers its room still needs, then cross off any blocked by an equal number within range in its row or column. The survivors are the only legal values, and a cell left with one candidate is a forced placement.

Apply the techniques in order: drop in the one-cell rooms, lock the small rooms, run the spacing eliminations, then work the room-and-line crossings, looping back as the grid fills. On Puzzle Lair every Ripple Effect is guaranteed solvable by logic alone, so if you are stuck there is always a deduction waiting, never a guess. Larger grids with big rooms and long-reaching numbers are what make the hard set a genuine workout.

Frequently asked questions

What is Ripple Effect?: Ripple Effect, also called Hakyuu, is a logic puzzle played on a grid divided into outlined rooms. Each room of N cells must contain every number from 1 through N once, and identical numbers must keep their distance: a number N cannot repeat within N cells in the same row or column. Diagonal repeats are allowed.
What is the spacing rule in Ripple Effect?: The spacing rule says identical numbers must ripple apart. Two equal numbers N need at least N cells between them in the same row or column. So two 1s cannot be adjacent in a line, two 2s need two cells between them, and two 3s need three. The rule only applies along rows and columns, never diagonals.
How do you start a Ripple Effect puzzle?: Begin with the one-cell rooms, which are always 1, then fill the smallest rooms whose limited range forces a value. Each number you place blocks equal numbers along its row and column through the spacing rule, which quickly narrows neighbouring rooms. Work outward from the small rooms toward the larger ones.
Can the same number appear more than once in Ripple Effect?: Yes, across different rooms. The same number can appear many times in the grid, and even twice in one row or column, as long as the two copies are far enough apart to satisfy the spacing rule. What it cannot do is repeat within a single room, since each room holds 1 up to its size exactly once.
Does solving Ripple Effect ever require guessing?: No. A well-made Ripple Effect has exactly one solution reachable by pure logic. Every Puzzle Lair Ripple Effect is generated and verified to be solvable without guessing, so being stuck means there is a deduction you have not spotted yet, often a spacing elimination or a room-and-line crossing you have not run. When you think the grid is complete, press Check to test the board. There is no mistake limit.

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