Rules -- Bridged Series

Bridged Series was invented by the Japanese puzzle company Nikoli (under the name Hashiwokakero).

1. Draw horizontal and vertical bridges (diagonal bridges are not allowed) between the islands according to the following rules.
2. A number on an island indicates how many bridges are connected to that island.
3. At most two bridges can connect a pair of islands.
4. A bridge may not cross over an island or another bridge.
5. All of the islands must be connected via the bridges. (It must be possible to get from any island to any other island using the bridges.)

Rules -- Solomon's Keep

Solomon's Keep was invented by the Japanese puzzle company Nikoli (under the name Five Cells – that's a transliteration, not a translation, believe it or not).

1. Divide the grid along the grid lines into pentominoes (regions containing exactly five cells each).
2. A number in a cell represents how many edges of that cell are borders of pentominoes (including the perimeter of the grid).

Rules -- Ellbound

Ellbound was invented by the Japanese puzzle company Nikoli (under the name Sashigane, which refers to a carpenter's square).

1. Divide the grid into L-shaped blocks, each consisting of an elbow, a horizontal arm extending from the elbow to another cell in the same row as the elbow, and a vertical arm extending from the elbow to another cell in the same column as the elbow.
2. A cell with a circle in it is the elbow of its corresponding block. If the circle has a number in it, that number represents how many cells are in that block.
3. A cell with an arrow in it is the tip of one of the arms of its corresponding block, and the arrow points to the elbow of that block.

Rules -- Dominnocuous

Dominnocuous was invented by the Japanese puzzle company Nikoli (under the name Norinori).

1. Shade in some cells such that every region contains exactly two shaded cells, and every shaded cell shares an edge with exactly one other shaded cell.

Rules -- Proof of Quilt

Proof of Quilt was invented by the Japanese puzzle company Nikoli (under the name Shakashaka) in 2008. 

1. Place black isosceles right triangles in some of the white cells in the grid. Each triangle must occupy exactly half of its cell, but may be in one of four orientations (◢, ◣, ◤, or ◥). A white cell may only contain one triangle.
2. Every contiguous region of white must be shaped like a rectangle (or a square).
3. A number in a black cell represents how many triangles share an edge with that cell.

Rules -- Spirits of Serpentine

Spirits of Serpentine was invented by the Japanese puzzle company Nikoli (under the name Hebi-Ichigo) in early 2009.

1. Locate several snakes in the white cells of the grid. Each snake consists of five cells, numbered 1 (the head) through 5 (the tail). Consecutively numbered cells within a snake must share an edge.
2. No two snakes may overlap or share an edge.
3. No snake may see another snake. A snake's eyes are on the side of its head opposite the number 2 cell. It can only see in that direction, in a straight line, up to the edge of the grid or the nearest black cell (whichever is closer). (See this illustrated example.)
4. A cell containing a number and an arrow represents the first number encountered in the row or column pointed at by the arrow, up to the edge of the grid or the nearest black cell (whichever is closer). A 0 means that no snake is encountered in this area.

Rules -- The Inner Limits

The Inner Limits was invented by the Japanese puzzle company Nikoli (under the name Bag, although the name Corral is probably more well-known amongst the global puzzle community).

1. Draw a single loop along the grid lines. The loop may not cross itself or branch off. In other words, the interior of the loop will be a single polygon.
2. Every number must be contained inside the loop.
3. A number indicates how many grid cells, including the cell itself, lie in an uninterrupted horizontal or vertical line from that cell, up to the nearest edges of the loop.

Rules -- Tatami For Now

Tatami For Now was invented by the Japanese puzzle company Nikoli (under the name Tatamibari). The puzzle is based on tatami mats, a traditional Japanese flooring; it is considered bad luck to have four tatami mats sharing a corner.

1. Divide the grid into rectangles (squares count as rectangles) along the grid lines in accordance with the following rules.
2. Every piece must contain exactly one symbol (+, -, or |).
3. Every piece containing a + must be square. Every piece containing a - must be wider than it is tall. Every piece containing a | must be taller than it is wide.
4. No four pieces may meet at a corner.

Rules -- Block Band

Block Band was invented by the Japanese puzzle company Nikoli (under the name Mochikoro).

1. Determine whether each cell is white or black according to the following rules.
2. No 2x2 cell area within the grid may contain all black cells.
3. The white cells must all form rectangle-shaped "islands". No two islands may be adjacent horizontally or vertically; however, the islands must all be connected through their corners.
4. No cell with a number in it may be black. Every cell with a number in it must be part of an island containing that many white cells. Every island must contain at most one number (although an island may contain no numbers).

Rules -- Circumnavi-Gates

Circumnavi-Gates was invented by the Japanese puzzle company Nikoli (under the name Suraromu).

1. Draw a single loop, starting and ending at the numbered circle. The loop may only travel horizontally or vertically, and never diagonally (so all turns are of 90 degrees). The loop may only turn at the centers of the grid cells. The loop may not cross itself or branch off. In other words, the interior of the loop will be a single polygon.
2. The dotted lines are called gates. The loop must pass straight through every gate exactly once, by traversing exactly one cell in each gate. (The number in the circle represents the total number of gates, and is included as a convenience.)
3. A numbered black cell represents the order in which the loop passes through the gate which touches that black cell. (If a numbered black cell is next to more than one gate, then the number refers only to the gate which has that same number on both ends.) A gate numbered 1 must be the first gate visited in the loop, starting from the circle and going in one of the two possible directions, a gate numbered 2 must be the second gate visited, and so forth. The other gates may be passed through in any order.

Rules -- Prev-Arrow-Cation

Prev-Arrow-Cation was invented by the Japanese puzzle company Nikoli (under the name Yajisan-Kazusan).

1. Determine whether each cell is white or black according to the following rules.
2. A white cell containing a number and an arrow represents how many black cells are in the row or column pointed at by the arrow.
3. A cell containing a number and an arrow may be shaded in; if so, the clue in it becomes meaningless, and may or may not be true.
4. No two black cells may share an edge. All of the white cells must be connected to each other through their edges.

Rules -- Ripple Play

Also known as Ripple Effect or Hakyuu Kouka.

1. Place a single positive integer in every empty cell.
2. Every region of the grid must contain consecutive numbers starting at 1, up through the number of cells in that region. (For instance, a 4-cell region must contain the numbers 1 through 4.)
3. Any two occurrences of the same number in one row or column must have at least that number of other cells between them. (For instance, two 2's in the same row or column must have at least two other cells between them.)

Rules -- Reunion Tour

AKA Numberlink.

1. Draw paths that connect the pairs of identical numbers on the grid. The paths may only travel horizontally or vertically, and never diagonally (so all turns are of 90 degrees). The paths may only turn at the centers of cells.
2. The paths may not cross each other, pass through other numbers, or otherwise share cells.

Rules -- Writer's Block

1. Divide the grid into pieces along the grid lines in accordance with the following rules.
2. Every set of symbols shown below the grid must be contained in a number of pieces containing those symbols, and no others. The number after the times sign indicates how many pieces must contain that set of symbols; for example, ABCDE × 5 means that 5 pieces must have one each of the letters A, B, C, D, and E.

Rules -- Quad-Wrangle

Quad-Wrangle was invented by the Japanese puzzle company Nikoli (under the name Shikaku).

1. Divide the grid into pieces along the grid lines in accordance with the following rules.
2. Every piece must be shaped like a rectangle. (A square counts as a rectangle.)
3. Each piece must contain exactly one number, which represents the area of that piece in squares.

Rules -- Artist's Block

Artist's Block was invented by the Japanese puzzle company Nikoli (under the name Tentai Show).

1. Divide the grid into black and white pieces along the grid lines, according to the following rules. (The solution will form a picture.)
2. Every piece must contain exactly one entire dot.
3. Every piece must have 180-degree rotational symmetry, with the dot being at the center of symmetry for that piece.
4. Every piece must match the color of its corresponding dot.

Rules -- Blackbarrier Jam

Blackbarrier Jam was invented by the Japanese puzzle company Nikoli (under the name Kurodoko, FKA Where is Black Cells). It is one of several of their puzzles based on the unique rules regarding the placement of black cells in Japanese crosswords.

1. Determine whether each cell is white or black according to the following rules.
2. No numbered cell may be black.
3. A number indicates how many grid cells, including the cell itself, lie in an uninterrupted horizontal or vertical line from that cell, up to the perimeter of the puzzle, or a black cell (whichever is closer).
4. No two black cells may share an edge. All of the white cells must be connected to each other through their edges.

Rules -- Numeral Crossing

I do not know the origin of this type of puzzle. It's just been around for a long time. Nikoli calls it Nansuke.


1. Place a single digit in each white cell of the grid.
2. A horizontal or vertical group of two or more consecutive white cells, bounded on both sides by black cells or the edge of the grid, is called an entry. Every entry, reading from left to right or from top to bottom, must be one of the numbers listed below the grid. Every number listed below the grid must appear as exactly one entry.

Rules -- Seek and Spell

Seek and Spell was invented by the Japanese puzzle company Nikoli (under the name Kanaore). To my knowledge, I am the only person who makes this kind of puzzle in a language other than Japanese.
1. Write a single one of the 26 letters of the English alphabet in each cell of the grid.
2. It must be possible to spell each of the words listed below the grid (excluding spaces, punctuation, and any other symbols besides the 26 letters of the English alphabet) by starting in the numbered cell corresponding to the number shown alongside that word, moving one cell in the direction indicated by the arrow, and then continuing to move one cell at a time up, down, left, or right to complete the word.
3. No cell may be used more than once in a single word, although you may use the same cell in multiple words.

Rules -- Totally Awesum

This puzzle, also known as Kakuro, is often thought of as a Japanese puzzle craze; however, the puzzle was actually invented by Dell Magazines (under the name Cross Sums), an American company, and was adopted by the Japanese puzzle company Nikoli later.

Special thanks to Lomont's Cross Sums for streamlining the process of test-solving and making PNG's for these puzzles.

1. Place a digit from 1 through 9 inclusive in each white cell of the grid.
2. A horizontal or vertical group of consecutive white cells, bounded on both sides by black cells or the edge of the grid, is called an entry. A number in a black cell above a diagonal line represents the sum of the digits in the horizontal entry to its right. A number in a black cell below a diagonal line represents the sum of the digits in the vertical entry below it.
3. No digit may be repeated within an entry.