Japanese Logic Puzzles Online — Free Japanese Logic Puzzles
Japanese logic puzzles are some of the most elegant brain teasers ever created. Originating from Japan — most famously through the puzzle publisher Nikoli — these pen-and-paper puzzles challenge you to fill grids, shade cells, draw loops, and place objects using nothing but pure deductive reasoning. No math tricks, no trivia, no guesswork — just logic.
Sudoku put Japanese logic puzzles on the global map in the mid-2000s, but it's only the tip of the iceberg. Nikoli alone has invented or popularized dozens of puzzle types since the 1980s, and new variants continue to appear in competition circuits and puzzle magazines worldwide.
The best part? Many of these puzzles are now available to play free online. No downloads, no sign-ups — just open your browser and start solving. Below you'll find over 30 Japanese logic puzzle types, each with a short explanation of how it works. Wherever we offer a free browser version, there's a direct link so you can jump straight in.
What Are Japanese Logic Puzzles?
The term “Japanese logic puzzle” generally refers to grid-based deduction puzzles that were invented or popularized in Japan. The single biggest name in the genre is Nikoli, a Tokyo-based publisher founded in 1980 that has created an astonishing number of original puzzle types. Many puzzles you might not realize are Japanese — like Nonograms, Kakuro, and Slitherlink — were either invented by Japanese designers or first brought to a wide audience through Nikoli's magazines.
What all Japanese logic puzzles share:
- A grid — usually square, occasionally rectangular or irregular.
- Simple rules — every puzzle type can be explained in a few sentences.
- A unique solution — a well-crafted puzzle has exactly one answer, reachable through logic alone.
- No guessing — trial and error is never necessary. Every step can be deduced.
- Elegant design — Nikoli puzzles are famously hand-crafted, with an emphasis on beauty and flow.
Whether you call them Nikoli puzzles, Japanese pencil puzzles, or simply logic puzzles, the appeal is the same: a clean set of rules, a blank grid, and the deep satisfaction of cracking it with nothing but your mind.
Puzzle Categories
We've organized the puzzles into five families. Click a category to jump straight to it:
- Number Placement Puzzles — fill grids with digits following uniqueness or arithmetic rules
- Shading & Painting Puzzles — decide which cells to shade black or leave white
- Loop & Path Puzzles — draw a continuous loop or connect paths through the grid
- Object Placement Puzzles — position objects like light bulbs or stars using clues
- Region & Connection Puzzles — divide the grid into regions or build networks
1. Number Placement Puzzles
These are the Japanese logic puzzles most people encounter first. You're given a grid and must fill it with numbers so that every digit obeys the stated rules. No advanced math required — it's all about logical elimination and careful deduction.
Sudoku
The undisputed king of Japanese logic puzzles and the world's most popular puzzle. Fill a 9×9 grid so that every row, every column, and every 3×3 box contains the digits 1–9 exactly once. Though Sudoku's roots trace back to a Swiss mathematician and an American magazine, it was the Japanese publisher Nikoli who gave it the name “Sudoku” (short for “the digits must remain single”) and popularized it worldwide. Difficulty ranges from gentle warm-ups to diabolical grids requiring advanced techniques like X-Wing and Swordfish.
Kakuro
Often called a cross-sum or number crossword, Kakuro uses a crossword-style grid where each “run” of white cells must add up to the clue shown at its start. Digits 1–9 can each appear only once per run. Nikoli has published Kakuro since the 1980s under the name “Kasan Kurosu”, and it remains one of the publisher's most popular offerings. It blends the satisfaction of Sudoku with light arithmetic.
KenKen
Invented by Japanese math teacher Tetsuya Miyamoto, KenKen (also known as KenDoku or Mathdoku) asks you to fill an n×n grid with 1–n so that no digit repeats in any row or column. Groups of cells (“cages”) are marked with a target number and an arithmetic operation (+, −, ×, ÷) that the digits inside must satisfy. Miyamoto designed KenKen as a classroom tool to make math fun, and it quickly became a global phenomenon.
Futoshiki
The name means “not equal” in Japanese. Fill an n×n grid with digits 1–n so that no number repeats in any row or column. The twist: inequality signs (< and >) between certain cells constrain which digit can be larger. Futoshiki is an excellent entry point into Japanese logic puzzles — the rules are dead simple, but harder grids demand genuine deductive skill.
Fillomino (Polyominous)
A Nikoli original. Fill every cell with a number so that each group of connected cells sharing the same number forms a polyomino whose size equals that number. For example, a group of 4s must cover exactly four connected cells. Clue numbers are given; the rest you deduce. Unlike most number puzzles, Fillomino doesn't have fixed regions — you discover them as you solve. This emergent quality makes it a favorite among puzzle enthusiasts.
Hitori
Published by Nikoli, Hitori (meaning “alone” or “one person”) flips the usual puzzle formula on its head. The grid starts completely filled with numbers, and your job is to shade out duplicates so that no digit appears more than once in any row or column. Shaded cells can never be orthogonally adjacent, and all unshaded cells must remain connected. Instead of filling in, you're eliminating.
Suguru (Tectonics / Number Blocks)
Created by Japanese puzzle designer Naoki Inaba, Suguru divides the grid into irregular regions of varying sizes. Fill each region with the digits 1 through n, where n is the number of cells in that region. The catch: no two identical digits can be adjacent — not even diagonally. Suguru puzzles are compact and quick to solve at easy levels but deceptively tricky at harder ones.
Killer Sudoku
A hybrid of Sudoku and Kakuro that became hugely popular in Japan. The standard Sudoku rules apply (1–9 in every row, column, and 3×3 box), but instead of given digits you get dashed cages with sum totals. Digits within a cage must add up to its total and cannot repeat. Killer Sudoku has a devoted global following and regularly appears in the World Puzzle Championship. Sometimes called “Samunamupure” in Japanese puzzle magazines.
Ripple Effect (Hakyuu)
A Nikoli original known in Japanese as Hakyuu (“ripple”). The grid is divided into rooms; fill each room with digits 1–n (where n is the room's size). If two identical digits appear in the same row or column, they must be at least that digit apart. For example, two 3s in the same column need at least three cells between them. This spacing rule is unlike anything else in the genre and creates wonderfully tricky deductions.
Sukoro
A lesser-known Nikoli gem. Each cell is either empty or contains a digit (1–4). The digit tells you how many of its orthogonal neighbors also contain a digit. All numbered cells must form a single connected group, and no two identical digits can be orthogonally adjacent. Sukoro is compact and approachable, yet the interplay of constraints can be surprisingly deep.
2. Shading & Painting Puzzles
In shading puzzles you decide, for each cell, whether it's filled (black) or empty (white). Clue numbers and connectivity rules guide your decisions. Japanese puzzle publishers have produced an extraordinary number of shading puzzle variants, and many of Nikoli's most beloved creations fall into this category.
Nonograms (Picross / Griddlers)
Independently invented by Japanese graphics editor Non Ishida and Japanese designer Tetsuya Nishio in 1987, Nonograms are arguably the second most famous Japanese logic puzzle after Sudoku. Each row and column has a sequence of clue numbers describing consecutive runs of shaded cells. Work through the clues logically, and a pixel-art picture gradually emerges from the grid. Also known as Picross, Griddlers, Hanjie, or Paint by Numbers.
Nurikabe
One of Nikoli's most elegant inventions. Numbered cells are “islands”; shade the remaining cells to form a single connected “sea.” Each island must contain exactly as many white cells as its number indicates, islands can't touch each other orthogonally, and the sea can never form a 2×2 block. The name comes from a creature in Japanese folklore — the nurikabe, an invisible wall that blocks travelers.
Heyawake
A Nikoli classic whose name translates to “divided rooms.” The grid is divided into rectangular rooms, some containing a number. Shade cells so that: no two shaded cells are adjacent, all unshaded cells form one connected group, no horizontal or vertical line of unshaded cells spans more than two rooms, and each numbered room contains exactly that many shaded cells. The room-spanning rule makes Heyawake uniquely tricky among shading puzzles.
Kuromasu (Where is Black Cells?)
Published by Nikoli under the charmingly literal title “Where is Black Cells?”, Kuromasu places numbers in some cells indicating how many white cells are visible from that cell in all four orthogonal directions (the numbered cell counts itself). Shade the remaining cells black so that no two black cells are adjacent and all white cells stay connected. Clean, elegant, and deeply satisfying.
Norinori
A Nikoli original. Shade exactly two cells in every region. Every shaded cell must be part of a domino (a 1×2 or 2×1 pair of adjacent shaded cells), but a single domino can span two different regions. Norinori is fast and approachable at small sizes but scales up to brain-bending grids. Its domino constraint creates elegant cascading logic.
LITS (Nuruomino)
Another Nikoli original. Place exactly one tetromino (an L, I, T, or S shape made of four cells) in each region. All tetrominoes must form a single connected group, but two tetrominoes of the same shape can never touch each other by a side. The shaded cells can never form a 2×2 square. LITS is one of the most satisfying Japanese region-based shading puzzles.
Shakashaka
A visually distinctive Nikoli puzzle. Place right triangles (in four possible orientations) into white cells so that every remaining white space forms a rectangle or square. Numbered black cells indicate how many of their orthogonal neighbors contain a triangle. Shakashaka exercises spatial reasoning in ways most Japanese logic puzzles don't, and the resulting patterns are oddly beautiful.
Cave (Corral / Bag)
Known as “Bag” in Nikoli's publications. Determine which cells are “inside” and “outside” a cave. Inside cells form a single connected region with no enclosed holes. Numbered cells are always inside and can see exactly that many inside cells in their row and column (including themselves). The boundary between inside and outside forms a single closed loop. Cave puzzles are elegant and highly visual.
Mochikoro
A Nikoli shading puzzle where you shade cells so that: each group of connected white cells forms a rectangle containing exactly one number (and the number equals the rectangle's area), the shaded cells form one connected group, and no 2×2 block is entirely shaded. Think of it as an inverted Shikaku — instead of drawing rectangles, you shade everything that isn't one.
3. Loop & Path Puzzles
In loop puzzles your pencil (or mouse) literally draws: you construct a single closed loop or connect paths through the grid. Nikoli has produced some of the genre's finest loop puzzles, and they're wonderfully satisfying in digital form where you can draw and erase segments freely.
Slitherlink (Fences / Loop the Loop)
One of Nikoli's greatest hits. Draw a single non-crossing, non-branching loop along the edges of a square grid. Some cells contain a number (0–3) that tells you exactly how many of that cell's four edges are part of the loop. The interaction between neighboring clues creates cascading deductions that feel incredibly satisfying to unravel. Slitherlink is a staple of the World Puzzle Championship.
Masyu
A Nikoli puzzle whose name means “evil influence.” Draw a closed loop that passes through every circle on the grid. At a white circle, the loop must go straight through but must turn on at least one of the neighboring cells. At a black circle, the loop must turn 90° but must go straight through both cells on either side. The rules look fiddly on paper, but in practice the logic flows beautifully.
Numberlink (Arukone)
Published by Nikoli under the name “Numberlink” (and sometimes “Arukone”). Pair up matching numbers by drawing non-crossing paths between them. In well-made Numberlink puzzles, the paths fill every cell of the grid. There's no arithmetic involved — it's pure spatial reasoning and deceptively addictive.
Yajilin (Arrow Puzzle)
A Nikoli original that cleverly combines loop-drawing with shading. Draw a single closed loop on the grid. Some cells contain an arrow and a number — the number tells you how many shaded cells lie in the arrow's direction. Shaded cells sit outside the loop and can never be adjacent. The interplay between the loop and the shading constraints makes Yajilin uniquely satisfying.
Country Road
A Nikoli loop puzzle. Draw a single closed loop that visits every region at least once. If a region contains a number, the loop must pass through exactly that many cells in that region. The loop can never pass through two consecutive cells that are both outside the loop and belong to different regions. Country Road is a satisfying blend of loop logic and regional reasoning, and a favorite in puzzle competitions.
Gokigen Naname (Slant)
Published by Nikoli, the name means “diagonal.” Place a diagonal line (either \ or /) in every cell. Numbers at the grid intersections tell you how many diagonals touch that corner. All resulting white regions (formed by the diagonal lines) must be distinct — no two white regions can share an edge. Gokigen Naname is fast-paced and surprisingly addictive, with a pleasing visual quality to the finished grid.
Shirokuro
A Nikoli path puzzle. The grid contains white and black circles. Connect each white circle to a black circle with a path, forming pairs. Paths travel orthogonally, never cross, and every circle must be used exactly once. All cells in the grid must be used by exactly one path. Shirokuro has a clean, elegant feel that rewards careful planning.
4. Object Placement Puzzles
Instead of numbers or shading, these Japanese logic puzzles ask you to place specific objects — light bulbs, stars, or other markers — according to given rules. The underlying logic is always the same: deduce where each object must (or can't) go.
Light Up (Akari)
One of Nikoli's most intuitive and popular puzzles. Place light bulbs on the grid to illuminate every white cell. A bulb lights its entire row and column until blocked by a black wall. No bulb can shine on another bulb. Numbered walls tell you exactly how many of their orthogonal neighbors are bulbs. The “light beam” visual makes the logic easy to follow, and harder puzzles can be genuinely challenging.
Dosun-Fuwari
A charming Nikoli puzzle. Place one black (heavy) block and one white (light) block in each region. Black blocks “fall” to the bottom due to gravity (they must rest on the floor or on another block), while white blocks “float” to the top (they must touch the ceiling or the underside of another block). No two blocks of the same color can be orthogonally adjacent. The gravity mechanic gives Dosun-Fuwari a playful, physical quality unique among logic puzzles.
Yajisan-Kazusan
A Nikoli puzzle closely related to Yajilin but with a twist. Some cells contain an arrow and a number indicating how many shaded cells lie in that direction. You shade cells to satisfy all the clues — but here's the catch: shaded cells can cover clues, making those clues irrelevant (they no longer need to be true). No two shaded cells can be adjacent, and all unshaded cells must remain connected. The ability to “silence” clues by shading them adds a fascinating layer of meta-deduction.
5. Region & Connection Puzzles
These puzzles focus on dividing the grid into areas or building networks. You're drawing borders, connecting nodes, or partitioning space — always guided by numeric or spatial clues. Nikoli has produced many of the genre's defining region puzzles.
Shikaku (Rectangles)
A Nikoli classic. Divide the grid into non-overlapping rectangles (or squares). Each rectangle must contain exactly one number, and that number equals the rectangle's area. Shikaku is wonderfully spatial — you're essentially tiling a floor, and the logic of fitting pieces together is deeply satisfying. A great gateway into region-based Japanese puzzles.
Galaxies (Tentai Show)
Published by Nikoli as “Tentai Show” (meaning “astronomical show”). Divide the grid into regions, each containing exactly one dot. Every region must be rotationally symmetric around its dot — spin it 180° and it looks the same. The shapes you discover are often surprising and beautiful. Galaxies is one of the most visually rewarding Japanese logic puzzles.
Hashi (Hashiwokakero / Bridges)
A Nikoli favorite whose full name, Hashiwokakero, means “build bridges.” Numbered circles (“islands”) sit on the grid. Connect them with horizontal or vertical bridges (one or two between any pair). Each island's number equals its total bridge count. All islands must be connected into a single network, and bridges can't cross. Hashi is beautifully tactile and one of the best gateway puzzles for Japanese logic puzzle beginners.
Tatamibari
A Nikoli puzzle inspired by tatami mat flooring. Divide the grid into rectangles (or squares), each containing exactly one symbol. A + means the region is a square, a − means it's wider than tall, and a | means it's taller than wide. No four region corners may meet at a single point (the “tatami condition” — a rule from traditional Japanese mat-laying). Fans of Shikaku and Galaxies will love it.
Nanro
A Nikoli region puzzle. The grid is divided into regions, some containing a number. Fill some cells with numbers so that: each region's filled cells all show the same digit equal to the count of filled cells in that region, filled cells form a single connected group, and no 2×2 area is entirely filled. Nanro is less well-known than other Nikoli puzzles but offers a unique and highly satisfying solving experience.
Makaro
A Nikoli puzzle that blends number placement with region logic. The grid is divided into rooms; fill each room with digits 1–n (where n is the room's size). Arrow clues on the boundary between rooms indicate that the largest number among the adjacent cells in the arrow's direction is in the pointed cell. No two identical digits can be orthogonally adjacent across room boundaries. Makaro is a newer addition to the Nikoli lineup that has earned a dedicated following.
Sashigane
A Nikoli puzzle where you divide the grid into L-shaped regions. Each region is an L-shape (exactly one right-angled bend). Some cells contain arrows pointing toward the bend of their L, and some cells contain circles marking the corner of the bend. Numbers, if given, indicate the total size of the L. Sashigane is niche but rewards solvers who enjoy spatial-geometric deduction.
Ready to Start Solving?
Whether you're a Sudoku veteran looking for your next obsession or you've never tried a Japanese logic puzzle, there's something on this list for you. The beauty of these puzzles is their range: from five-minute warm-ups like Suguru and Hitori to multi-hour challenges like advanced Slitherlinks and large Nonogram grids.
We offer free playable versions of over 20 of the Japanese logic puzzle types listed above — all running right in your browser with no download or account needed. Pick a puzzle, click the play button, and discover why these elegant Japanese creations have captivated millions of solvers worldwide.
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