🕷️ Crawler Inspector

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Direct Parameter Lookup

Raw Queries and Responses

1. Shard Calculation

Query:

Response:

Calculated Shard: 70 (from laksa104)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa070.int.ahrefs:8124/' \
  -H 'Content-Type: text/plain' \
  -H 'X-ClickHouse-Database: crawler3' \
  -H 'Authorization: Basic YXBpOg==' \
  -d 'SELECT getAhrefsURLFromUnparsed(src_unparsed) AS found_url, ifNull(toUnixTimestamp(download_stamp), 0) AS crawl_time, ifNull(toUnixTimestamp(props_url_first_seen), 0) AS first_indexed_time, download_http_code AS http_code, src_unparsed AS src_unparsed, src_root_hash AS src_root_hash, history_drop_reason AS history_drop_reason, meta_title AS meta_title, meta_descriptions AS meta_descriptions, attrs_boilerpipe_text AS attrs_boilerpipe_text, attrs_markdown AS attrs_markdown, attrs_readable_markdown AS attrs_readable_markdown, meta_canonical AS meta_canonical FROM crawler3.page_info_local FINAL PREWHERE (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://www.sudokuwiki.org/sudoku.htm\')), getAhrefsUnparsedNoserviceFromURL(\'https://www.sudokuwiki.org/sudoku.htm\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/www.sudokuwiki.org\/sudoku.htm","crawl_time":1776188726,"first_indexed_time":1574408454,"http_code":200,"src_unparsed":"org,sudokuwiki!www,\/sudoku.htm s443","src_root_hash":"16065194319553459070","history_drop_reason":null,"meta_title":"Sudoku Solver by Andrew Stuart","meta_descriptions":["Sudoku Solver by Andrew Stuart. Shows the logic behind solving Sudoku square by square."],"attrs_boilerpipe_text":"Welcome to my Sudoku page\nSince I first studied Sudoku in May 2005 I think I've finally got a handle on this puzzle. My original\r\n\t\t\t\tintention was to prove to myself that a small number of simple strategies existed that could solve\r\n\t\t\t\tevery sudoku. How wrong I was. Sudoku has enormous depth and while this solver has grown up enough\r\n\t\t\t\tto crack 99.9% of puzzles there are many weird and wonderful examples that defeat it. The main\r\n\t\t\t\treason to keep this solver in development is to analyse these difficult ones. To that end I've added\r\n\t\t\t\tnew graphical tools and features which I hope you'll enjoy.\nI am continuing to document the various strategies that I and many other people have invented.\r\n\t\t\t\tThese are available\nhere\n.\nI've tried to give credit where credit is due. Please update me if I have\r\n\t\t\t\tmissed anyone or need to make a correction.\nI am now working independently on puzzle creation, especially at\nwww.str8ts.com\n.\nAll feedback, comments, arguments, bug reports and strategy ideas are welcome. There is a\nFEEDBACK\nform with a column displaying comments and questions.\r\n\t\t\t\tMany thanks to all the people who have done so and helped improve this solver.\nOriginal version 1.01\n28th May 2005\r\n\t\t\t\t-\nFull version history here\nNew: Candidate and cell colouring\nMany people have written to me to comment about multiple solutions for a given Sudoku. There\r\n\t\t\t\tare no logical tricks the solver can use to detect this other than to not complete correctly.\r\n\t\t\t\tThe only way to check this is to perform a brute force analysis which tests every possible\r\n\t\t\t\tlegal placement of a number. Computers are good at this and that's what the\nSolution Count\nbutton is for. Try this on any Sudoku to check whether if it is sane or not.\nStrategy Overview\n>\r\n\t\t\tTick and untick the check boxes to enable\/disabled specific strategies. \r\n\t\t\tThe first five 'basic' tests are the simplest and my advice is to allow the solver to use them\r\n\t\t\tas skipping may cause unexpected logic in later strategies.\n>\r\n\t\t    The order of these advanced strategies - and my inclusion of them in categories 'tough', 'diabolical'\r\n\t\t    and 'extreme' are my personal choice after close study and are roughly in order of complexity. While\r\n\t\t    the logic is different for each, you should be aware that there is considerable overlap in their\r\n\t\t    power to solve in certain situations. For example, X-Cycles are a subset of Alternating Inference Chains.\r\n\t\t    If you turn off X-Cycles the same elimination might turn up under AICs. Since March 2010 I have reworked\r\n\t\t    most chaining strategies to find the best and shortest chains - not necessarily the first one it happens to find.\n>\r\n\t\t    All strategies in the list have\nlinks to documentation\n, but it's worth describing what the first tests do:\nShow Possibles (Naked Singles)\n: For each unknown square we eliminate all\r\n\t\t    possibles where those numbers are known in each row, column and box. This may reveal a single\r\n\t\t    candidate, in which case we have a solution for that cell.\nHidden Singles\n: If a candidate\r\n\t\t    occurs once only in a row or column or box we can make it the solution to the cell.\nTest 2\n: In this test we check for 'naked'\nPairs and Triples\n.\r\n\t\t    For example, if we have two pairs, eg 3-4 and 3-4 in the same row, column or box, then both 3 and 4 must\r\n\t\t    occupy those squares (in what ever order). 3 and 4 can then be eliminated from\r\n\t\t    the rest of the row, column or box.\nTest 3\n: This test is for\nHidden Pairs\n,\nHidden Triples\nTest 4\n: Naked and Hidden Quads - much rarer but simply extends Pairs and Triples.\nTest 5\n: See\nPointing Pairs and Triples\nfor\r\n\t\t    a full explanation. This test helps us eliminate numbers in rows and columns outside the box.\nTest 6\n:\nBox\/Line Reduction\n.\r\n\t\t    We check the box against the rows and columns that intersect it for each number.\nIf this solver comes up with an error or it can't be solved, first use the\nSolution Count\nbutton to prove it has only one solution.\r\n\t\t    This uses a fast brute-force algorithm to check for all possible solutions. If it's valid,\r\n\t\t    please use the \"Email This Board\" button to send it to andrew@str8ts.com. I'd be very interested to study\r\n\t\t    examples that can't be solved on this page.","attrs_markdown":"|   |   |   |   |\n|---|---|---|---|\n| [![Solver App for Android](https:\/\/www.sudokuwiki.org\/images\/SudokuWiki_android.png)](https:\/\/www.sudokuwiki.org\/Sudoku_Solver_for_Android) | Sudoku Solver for AndroidUpdated 28 Jan 2026 [Read the update](https:\/\/www.sudokuwiki.org\/Sudoku_Solver_for_Android) | SudokuWiki.org Strategies for Popular Number Puzzles |   |\n\n- [Sign up for more](https:\/\/www.sudokuwiki.org\/SPHome.aspx)\n\n- [Main Page](https:\/\/www.sudokuwiki.org\/Main_Page)\n- [What's New](https:\/\/www.sudokuwiki.org\/Whats_New)\n- [Strategy Overview](https:\/\/www.sudokuwiki.org\/Strategy_Families)\n\n9x9 Solvers\n\n- [Sudoku Solver](https:\/\/www.sudokuwiki.org\/Sudoku.htm)\n- [Jigsaw Solver](https:\/\/www.sudokuwiki.org\/Jigsaw.aspx)\n- [Sudoku X Solver](https:\/\/www.sudokuwiki.org\/SudokuX.aspx)\n- [Windoku Solver](https:\/\/www.sudokuwiki.org\/Windoku.aspx)\n- [Colour Sudoku](https:\/\/www.sudokuwiki.org\/ColourSudoku.aspx)\n- [Killer Solver](https:\/\/www.sudokuwiki.org\/KillerSudoku.aspx)\n- [Killer Jigsaw Solver](https:\/\/www.sudokuwiki.org\/KillerJigsaw.aspx)\n\n6x6 Solvers\n\n- [6x6 Sudoku Solver](https:\/\/www.sudokuwiki.org\/Sudoku6x6.aspx)\n- [6x6 Killer Solver](https:\/\/www.sudokuwiki.org\/Killer6x6.aspx)\n- [6x6 KenKen Solver](https:\/\/www.sudokuwiki.org\/KenKen6x6.aspx)\n- [6x6 KenDoku Solver](https:\/\/www.sudokuwiki.org\/kendoku6x6.aspx)\n\nWeekly 'Unsolvable'\n\n- [Unsolvable Sudoku](https:\/\/www.sudokuwiki.org\/Weekly-Sudoku.aspx)\n- [Unsolvable Jigsaw](https:\/\/www.sudokuwiki.org\/Weekly-Jigsaw.aspx)\n- [Unsolvable Str8ts](https:\/\/www.str8ts.com\/weekly_str8ts.aspx)\n\nPuzzles to Play\n\n- [The Daily Sudoku](https:\/\/www.sudokuwiki.org\/Daily_Sudoku)\n- [Daily 6x6 Sudoku](https:\/\/www.sudokuwiki.org\/Daily_Mini_Sudoku)New\\!\n- [The Jigsaw Sudoku](https:\/\/www.sudokuwiki.org\/Daily_Jigsaw_Sudoku)\n- [The Daily Sudoku X](https:\/\/www.sudokuwiki.org\/Daily_Sudoku_X)\n- [The Daily Killer](https:\/\/www.sudokuwiki.org\/Daily_Killer_Sudoku.aspx)\n- [Daily Mini Killer](https:\/\/www.sudokuwiki.org\/Daily_Mini_Killer_Sudoku.aspx)\n- [Daily Killer Jigsaw](https:\/\/www.sudokuwiki.org\/Daily_Killer_Jigsaw.aspx)\n- [The Daily Kakuro](https:\/\/www.sudokuwiki.org\/Daily_Kakuro)\n- [The Daily KenKen](https:\/\/www.sudokuwiki.org\/Daily_KenKen.aspx)\n- [Daily Codewords](https:\/\/www.sudokuwiki.org\/Daily_Codewords)\n- [1 to 25](https:\/\/www.str8ts.com\/daily_1to25.aspx)\n- [The Daily Binairo](https:\/\/www.sudokuwiki.org\/DailyBinairo)\n- [Letterlicious](https:\/\/www.letterlicious.com\/Letterlicious_Home.aspx)\n- [Puzzle Packs](https:\/\/www.sudokuwiki.org\/ACSPuzzles.aspx)\n\nApps\n\n- [5 Daily Puzzles](https:\/\/www.sudokuwiki.org\/5_Daily_Puzzles_for_the_iPad)\n- [SudokuWiki Solver](https:\/\/www.sudokuwiki.org\/Sudoku_Solver_for_Android)\n\nStr8ts\n\n- [Home & Rules](https:\/\/www.str8ts.com\/str8ts)\n- [The Daily Str8ts](https:\/\/www.str8ts.com\/Daily_str8ts)\n- [Str8ts Books](https:\/\/www.str8ts.com\/New_Str8ts_Books)New\\!\n\nOther\n\n- [Latest Articles](https:\/\/www.sudokuwiki.org\/LatestArticles.aspx)\n- [Feedback](https:\/\/www.sudokuwiki.org\/sudokufeedback.aspx)\n- [Donate](https:\/\/www.sudokuwiki.org\/Donations)\n- [Syndicated Puzzles](https:\/\/www.syndicatedpuzzles.com\/)\n\n|   |   |   |\n|---|---|---|\n| Logged out | Please [report any bugs](https:\/\/www.sudokuwiki.org\/sudokufeedback.aspx) and feedback welcome |   |\n\nSudoku Solver\n\nSolve Path excludes unchecked strategies \\&\\#x2193\n\n|   |   |   |   |   |   |   |   |   |\n|---|---|---|---|---|---|---|---|---|\n|   |   |   |   |   |   |   |   |   |\n| Candidates can be Edited Highlighted Chained Coloured, Shown |   |   |   |   |   |   |   |   |\n| Enter clues  or solutions |   |   |   | Errors? \\[CRTL\\]+\\[F5\\] to clear and download the latest script files |   |   |   |   |\n|   |   |   |   |   |   |   |   |   |\n| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |\n|   |   | Version 2.59.1 Coordinate system: Letter\/Number rYcX    See [the Strategy Home Page](https:\/\/www.sudokuwiki.org\/Strategy_Families) for strategy guides |   |   |   |   |   |   |\n|   |   |   |   |   |   |   |   |   |\n| Show bi-value cells |   |   |   |   |   |   |   |   |\n| Show Strong (bi-location) links in |   |   |   |   |   |   |   |   |\n|   | Boxes |   | Rows |   | Columns |   |   |   |\n| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |\n|   |   |   |   |   |   |   |   |   |\n| A |   |   |   |   |   |   |   |   |\n| B |   |   |   |   |   |   |   |   |\n| C |   |   |   |   |   |   |   |   |\n| D |   |   |   |   |   |   |   |   |\n| E |   |   |   |   |   |   |   |   |\n| F |   |   |   |   |   |   |   |   |\n| G |   |   |   |   |   |   |   |   |\n| H |   |   |   |   |   |   |   |   |\n| J |   |   |   |   |   |   |   |   |\n|   |   |   |   |   |   |   |   |   |\n| 1 |   |   |   |   |   |   |   |   |\n| 2 |   |   |   |   |   |   |   |   |\n| 3 |   |   |   |   |   |   |   |   |\n| 4 |   |   |   |   |   |   |   |   |\n| 5 |   |   |   |   |   |   |   |   |\n| 6 |   |   |   |   |   |   |   |   |\n| 7 |   |   |   |   |   |   |   |   |\n| 8 |   |   |   |   |   |   |   |   |\n| 9 |   |   |   |   |   |   |   |   |\n\n|   |   |   |\n|---|---|---|\n| Welcome to my Sudoku page Since I first studied Sudoku in May 2005 I think I've finally got a handle on this puzzle. My original intention was to prove to myself that a small number of simple strategies existed that could solve every sudoku. How wrong I was. Sudoku has enormous depth and while this solver has grown up enough to crack 99.9% of puzzles there are many weird and wonderful examples that defeat it. The main reason to keep this solver in development is to analyse these difficult ones. To that end I've added new graphical tools and features which I hope you'll enjoy. I am continuing to document the various strategies that I and many other people have invented. These are available [here](https:\/\/www.sudokuwiki.org\/Strategy_Families). I've tried to give credit where credit is due. Please update me if I have missed anyone or need to make a correction. I am now working independently on puzzle creation, especially at [www.str8ts.com](https:\/\/www.str8ts.com\/). All feedback, comments, arguments, bug reports and strategy ideas are welcome. There is a [FEEDBACK](https:\/\/www.sudokuwiki.org\/sudokufeedback.aspx) form with a column displaying comments and questions. Many thanks to all the people who have done so and helped improve this solver.     **Original version 1.01 28th May 2005 - [Full version history here](https:\/\/www.sudokuwiki.org\/Sudoku_Solver___Version_History)**     New: Candidate and cell colouring ![](https:\/\/www.sudokuwiki.org\/puzimages\/CellCol2.png)      Many people have written to me to comment about multiple solutions for a given Sudoku. There are no logical tricks the solver can use to detect this other than to not complete correctly. The only way to check this is to perform a brute force analysis which tests every possible legal placement of a number. Computers are good at this and that's what the **Solution Count** button is for. Try this on any Sudoku to check whether if it is sane or not. |   | Strategy Overview \\> Tick and untick the check boxes to enable\/disabled specific strategies. The first five 'basic' tests are the simplest and my advice is to allow the solver to use them as skipping may cause unexpected logic in later strategies. \\> The order of these advanced strategies - and my inclusion of them in categories 'tough', 'diabolical' and 'extreme' are my personal choice after close study and are roughly in order of complexity. While the logic is different for each, you should be aware that there is considerable overlap in their power to solve in certain situations. For example, X-Cycles are a subset of Alternating Inference Chains. If you turn off X-Cycles the same elimination might turn up under AICs. Since March 2010 I have reworked most chaining strategies to find the best and shortest chains - not necessarily the first one it happens to find. \\> All strategies in the list have [links to documentation](https:\/\/www.sudokuwiki.org\/Strategy_Families), but it's worth describing what the first tests do: Show Possibles (Naked Singles) : For each unknown square we eliminate all possibles where those numbers are known in each row, column and box. This may reveal a single candidate, in which case we have a solution for that cell. Hidden Singles : If a candidate occurs once only in a row or column or box we can make it the solution to the cell. Test 2 : In this test we check for 'naked' [Pairs and Triples](https:\/\/www.sudokuwiki.org\/Naked_Candidates#NP) . For example, if we have two pairs, eg 3-4 and 3-4 in the same row, column or box, then both 3 and 4 must occupy those squares (in what ever order). 3 and 4 can then be eliminated from the rest of the row, column or box. Test 3 : This test is for [Hidden Pairs](https:\/\/www.sudokuwiki.org\/Hidden_Candidates#HP) , [Hidden Triples](https:\/\/www.sudokuwiki.org\/Hidden_Candidates#HT) Test 4 : Naked and Hidden Quads - much rarer but simply extends Pairs and Triples. Test 5 : See [Pointing Pairs and Triples](https:\/\/www.sudokuwiki.org\/Intersection_Removal) for a full explanation. This test helps us eliminate numbers in rows and columns outside the box. Test 6 : [Box\/Line Reduction](https:\/\/www.sudokuwiki.org\/Intersection_Removal#LBR) . We check the box against the rows and columns that intersect it for each number. If this solver comes up with an error or it can't be solved, first use the **Solution Count** button to prove it has only one solution. This uses a fast brute-force algorithm to check for all possible solutions. If it's valid, please use the \"Email This Board\" button to send it to andrew@str8ts.com. I'd be very interested to study examples that can't be solved on this page. |\n\nSolver created on 28-May-2005.   \n This page was last modified on 10-Apr-2026.  \n All code and design is copyright and for personal use only and may not be reproduced elsewhere.  \n [Copyright](https:\/\/www.sudokuwiki.org\/Copyright) Andrew Stuart @ [Syndicated Puzzles](https:\/\/www.syndicatedpuzzles.com\/), 2005-2025, [Privacy](https:\/\/www.sudokuwiki.org\/privacy)\n\n|   |   |   |\n|---|---|---|\n|   | All Solutions to a Sudoku |   |\n| ![Logo](https:\/\/www.sudokuwiki.org\/images\/sudoA.gif) |   |   |\n|   | Min-lex version: ([docs](https:\/\/www.sudokuwiki.org\/Sudoku_Min_Lex)) |   |\n|   | By Andrew Stuart, Rui Gonçalves and Jim White (min-lex) |   |\n\n|   |   |   |\n|---|---|---|\n|   | Attempting to minimise the number of clues... |   |\n| ![Logo](https:\/\/www.sudokuwiki.org\/images\/sudoA.gif) | Warning: This may run for a long time depending on the puzzle and appear to hang. Cancel if excessive. |   |\n|   | Removed:  Recursed  Still Going\\!  Finished\\! |   |\n\n|   |   |   |\n|---|---|---|\n|   | Email your puzzle to a friend |   |\n| ![Logo](https:\/\/www.sudokuwiki.org\/images\/sudoA.gif) |   |   |\n|   | Copy and paste the contents of the green box into your email program and send it off.  The links contain the puzzle which will load when your friend visits the Sudoku Solver. |   |\n\n|   |   |   |   |\n|---|---|---|---|\n|   |   | Import a Sudoku puzzle |   |\n| ![Logo](https:\/\/www.sudokuwiki.org\/images\/sudoA.gif) |   |   |   |\n|   | Paste in 81 numbers. Zeroes can be dots or other punctuation.  This importer can handle noisy formats like grids with lines and dots.  As long as there are 81 separated numbers.  Any number greater than 9 will be treated as a set of candidates. |   |   |","attrs_readable_markdown":null,"meta_canonical":null}

3. Robots.txt Check

Query:

Response:

4. Spam/Ban Check

Query:

Response:

5. Seen Status Check

ℹ️ Skipped - page is already crawled

📄

INDEXABLE

✅

CRAWLED

3 hours ago

🤖

ROBOTS ALLOWED

Page Info Filters

Filter	Status	Condition	Details
HTTP status	PASS	`download_http_code = 200`	HTTP 200
Age cutoff	PASS	`download_stamp > now() - 6 MONTH`	0 months ago
History drop	PASS	`isNull(history_drop_reason)`	No drop reason
Spam/ban	PASS	`fh_dont_index != 1 AND ml_spam_score = 0`	ml_spam_score=0
Canonical	PASS	`meta_canonical IS NULL OR = '' OR = src_unparsed`	Not set

Page Details

Property	Value
URL	https://www.sudokuwiki.org/sudoku.htm
Last Crawled	2026-04-14 17:45:26 (3 hours ago)
First Indexed	2019-11-22 07:40:54 (6 years ago)
HTTP Status Code	200
Meta Title	Sudoku Solver by Andrew Stuart
Meta Description	Sudoku Solver by Andrew Stuart. Shows the logic behind solving Sudoku square by square.
Meta Canonical	null
Boilerpipe Text	Welcome to my Sudoku page Since I first studied Sudoku in May 2005 I think I've finally got a handle on this puzzle. My original intention was to prove to myself that a small number of simple strategies existed that could solve every sudoku. How wrong I was. Sudoku has enormous depth and while this solver has grown up enough to crack 99.9% of puzzles there are many weird and wonderful examples that defeat it. The main reason to keep this solver in development is to analyse these difficult ones. To that end I've added new graphical tools and features which I hope you'll enjoy. I am continuing to document the various strategies that I and many other people have invented. These are available here . I've tried to give credit where credit is due. Please update me if I have missed anyone or need to make a correction. I am now working independently on puzzle creation, especially at www.str8ts.com . All feedback, comments, arguments, bug reports and strategy ideas are welcome. There is a FEEDBACK form with a column displaying comments and questions. Many thanks to all the people who have done so and helped improve this solver. Original version 1.01 28th May 2005 - Full version history here New: Candidate and cell colouring Many people have written to me to comment about multiple solutions for a given Sudoku. There are no logical tricks the solver can use to detect this other than to not complete correctly. The only way to check this is to perform a brute force analysis which tests every possible legal placement of a number. Computers are good at this and that's what the Solution Count button is for. Try this on any Sudoku to check whether if it is sane or not. Strategy Overview > Tick and untick the check boxes to enable/disabled specific strategies. The first five 'basic' tests are the simplest and my advice is to allow the solver to use them as skipping may cause unexpected logic in later strategies. > The order of these advanced strategies - and my inclusion of them in categories 'tough', 'diabolical' and 'extreme' are my personal choice after close study and are roughly in order of complexity. While the logic is different for each, you should be aware that there is considerable overlap in their power to solve in certain situations. For example, X-Cycles are a subset of Alternating Inference Chains. If you turn off X-Cycles the same elimination might turn up under AICs. Since March 2010 I have reworked most chaining strategies to find the best and shortest chains - not necessarily the first one it happens to find. > All strategies in the list have links to documentation , but it's worth describing what the first tests do: Show Possibles (Naked Singles) : For each unknown square we eliminate all possibles where those numbers are known in each row, column and box. This may reveal a single candidate, in which case we have a solution for that cell. Hidden Singles : If a candidate occurs once only in a row or column or box we can make it the solution to the cell. Test 2 : In this test we check for 'naked' Pairs and Triples . For example, if we have two pairs, eg 3-4 and 3-4 in the same row, column or box, then both 3 and 4 must occupy those squares (in what ever order). 3 and 4 can then be eliminated from the rest of the row, column or box. Test 3 : This test is for Hidden Pairs , Hidden Triples Test 4 : Naked and Hidden Quads - much rarer but simply extends Pairs and Triples. Test 5 : See Pointing Pairs and Triples for a full explanation. This test helps us eliminate numbers in rows and columns outside the box. Test 6 : Box/Line Reduction . We check the box against the rows and columns that intersect it for each number. If this solver comes up with an error or it can't be solved, first use the Solution Count button to prove it has only one solution. This uses a fast brute-force algorithm to check for all possible solutions. If it's valid, please use the "Email This Board" button to send it to andrew@str8ts.com. I'd be very interested to study examples that can't be solved on this page.
Markdown	\| \| \| \| \| \|---\|---\|---\|---\| \| [![Solver App for Android](https://www.sudokuwiki.org/images/SudokuWiki_android.png)](https://www.sudokuwiki.org/Sudoku_Solver_for_Android) \| Sudoku Solver for AndroidUpdated 28 Jan 2026 [Read the update](https://www.sudokuwiki.org/Sudoku_Solver_for_Android) \| SudokuWiki.org Strategies for Popular Number Puzzles \| \| - [Sign up for more](https://www.sudokuwiki.org/SPHome.aspx) - [Main Page](https://www.sudokuwiki.org/Main_Page) - [What's New](https://www.sudokuwiki.org/Whats_New) - [Strategy Overview](https://www.sudokuwiki.org/Strategy_Families) 9x9 Solvers - [Sudoku Solver](https://www.sudokuwiki.org/Sudoku.htm) - [Jigsaw Solver](https://www.sudokuwiki.org/Jigsaw.aspx) - [Sudoku X Solver](https://www.sudokuwiki.org/SudokuX.aspx) - [Windoku Solver](https://www.sudokuwiki.org/Windoku.aspx) - [Colour Sudoku](https://www.sudokuwiki.org/ColourSudoku.aspx) - [Killer Solver](https://www.sudokuwiki.org/KillerSudoku.aspx) - [Killer Jigsaw Solver](https://www.sudokuwiki.org/KillerJigsaw.aspx) 6x6 Solvers - [6x6 Sudoku Solver](https://www.sudokuwiki.org/Sudoku6x6.aspx) - [6x6 Killer Solver](https://www.sudokuwiki.org/Killer6x6.aspx) - [6x6 KenKen Solver](https://www.sudokuwiki.org/KenKen6x6.aspx) - [6x6 KenDoku Solver](https://www.sudokuwiki.org/kendoku6x6.aspx) Weekly 'Unsolvable' - [Unsolvable Sudoku](https://www.sudokuwiki.org/Weekly-Sudoku.aspx) - [Unsolvable Jigsaw](https://www.sudokuwiki.org/Weekly-Jigsaw.aspx) - [Unsolvable Str8ts](https://www.str8ts.com/weekly_str8ts.aspx) Puzzles to Play - [The Daily Sudoku](https://www.sudokuwiki.org/Daily_Sudoku) - [Daily 6x6 Sudoku](https://www.sudokuwiki.org/Daily_Mini_Sudoku)New\! - [The Jigsaw Sudoku](https://www.sudokuwiki.org/Daily_Jigsaw_Sudoku) - [The Daily Sudoku X](https://www.sudokuwiki.org/Daily_Sudoku_X) - [The Daily Killer](https://www.sudokuwiki.org/Daily_Killer_Sudoku.aspx) - [Daily Mini Killer](https://www.sudokuwiki.org/Daily_Mini_Killer_Sudoku.aspx) - [Daily Killer Jigsaw](https://www.sudokuwiki.org/Daily_Killer_Jigsaw.aspx) - [The Daily Kakuro](https://www.sudokuwiki.org/Daily_Kakuro) - [The Daily KenKen](https://www.sudokuwiki.org/Daily_KenKen.aspx) - [Daily Codewords](https://www.sudokuwiki.org/Daily_Codewords) - [1 to 25](https://www.str8ts.com/daily_1to25.aspx) - [The Daily Binairo](https://www.sudokuwiki.org/DailyBinairo) - [Letterlicious](https://www.letterlicious.com/Letterlicious_Home.aspx) - [Puzzle Packs](https://www.sudokuwiki.org/ACSPuzzles.aspx) Apps - [5 Daily Puzzles](https://www.sudokuwiki.org/5_Daily_Puzzles_for_the_iPad) - [SudokuWiki Solver](https://www.sudokuwiki.org/Sudoku_Solver_for_Android) Str8ts - [Home & Rules](https://www.str8ts.com/str8ts) - [The Daily Str8ts](https://www.str8ts.com/Daily_str8ts) - [Str8ts Books](https://www.str8ts.com/New_Str8ts_Books)New\! Other - [Latest Articles](https://www.sudokuwiki.org/LatestArticles.aspx) - [Feedback](https://www.sudokuwiki.org/sudokufeedback.aspx) - [Donate](https://www.sudokuwiki.org/Donations) - [Syndicated Puzzles](https://www.syndicatedpuzzles.com/) \| \| \| \| \|---\|---\|---\| \| Logged out \| Please [report any bugs](https://www.sudokuwiki.org/sudokufeedback.aspx) and feedback welcome \| \| Sudoku Solver Solve Path excludes unchecked strategies \&\#x2193 \| \| \| \| \| \| \| \| \| \| \|---\|---\|---\|---\|---\|---\|---\|---\|---\| \| \| \| \| \| \| \| \| \| \| \| Candidates can be Edited Highlighted Chained Coloured, Shown \| \| \| \| \| \| \| \| \| \| Enter clues or solutions \| \| \| \| Errors? \[CRTL\]+\[F5\] to clear and download the latest script files \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| 1 \| 2 \| 3 \| 4 \| 5 \| 6 \| 7 \| 8 \| 9 \| \| \| \| Version 2.59.1 Coordinate system: Letter/Number rYcX See [the Strategy Home Page](https://www.sudokuwiki.org/Strategy_Families) for strategy guides \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| Show bi-value cells \| \| \| \| \| \| \| \| \| \| Show Strong (bi-location) links in \| \| \| \| \| \| \| \| \| \| \| Boxes \| \| Rows \| \| Columns \| \| \| \| \| 1 \| 2 \| 3 \| 4 \| 5 \| 6 \| 7 \| 8 \| 9 \| \| \| \| \| \| \| \| \| \| \| \| A \| \| \| \| \| \| \| \| \| \| B \| \| \| \| \| \| \| \| \| \| C \| \| \| \| \| \| \| \| \| \| D \| \| \| \| \| \| \| \| \| \| E \| \| \| \| \| \| \| \| \| \| F \| \| \| \| \| \| \| \| \| \| G \| \| \| \| \| \| \| \| \| \| H \| \| \| \| \| \| \| \| \| \| J \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| \| 1 \| \| \| \| \| \| \| \| \| \| 2 \| \| \| \| \| \| \| \| \| \| 3 \| \| \| \| \| \| \| \| \| \| 4 \| \| \| \| \| \| \| \| \| \| 5 \| \| \| \| \| \| \| \| \| \| 6 \| \| \| \| \| \| \| \| \| \| 7 \| \| \| \| \| \| \| \| \| \| 8 \| \| \| \| \| \| \| \| \| \| 9 \| \| \| \| \| \| \| \| \| \| \| \| \| \|---\|---\|---\| \| Welcome to my Sudoku page Since I first studied Sudoku in May 2005 I think I've finally got a handle on this puzzle. My original intention was to prove to myself that a small number of simple strategies existed that could solve every sudoku. How wrong I was. Sudoku has enormous depth and while this solver has grown up enough to crack 99.9% of puzzles there are many weird and wonderful examples that defeat it. The main reason to keep this solver in development is to analyse these difficult ones. To that end I've added new graphical tools and features which I hope you'll enjoy. I am continuing to document the various strategies that I and many other people have invented. These are available [here](https://www.sudokuwiki.org/Strategy_Families). I've tried to give credit where credit is due. Please update me if I have missed anyone or need to make a correction. I am now working independently on puzzle creation, especially at [www.str8ts.com](https://www.str8ts.com/). All feedback, comments, arguments, bug reports and strategy ideas are welcome. There is a [FEEDBACK](https://www.sudokuwiki.org/sudokufeedback.aspx) form with a column displaying comments and questions. Many thanks to all the people who have done so and helped improve this solver. Original version 1.01 28th May 2005 - [Full version history here](https://www.sudokuwiki.org/Sudoku_Solver___Version_History) New: Candidate and cell colouring ![](https://www.sudokuwiki.org/puzimages/CellCol2.png) Many people have written to me to comment about multiple solutions for a given Sudoku. There are no logical tricks the solver can use to detect this other than to not complete correctly. The only way to check this is to perform a brute force analysis which tests every possible legal placement of a number. Computers are good at this and that's what the Solution Count button is for. Try this on any Sudoku to check whether if it is sane or not. \| \| Strategy Overview \> Tick and untick the check boxes to enable/disabled specific strategies. The first five 'basic' tests are the simplest and my advice is to allow the solver to use them as skipping may cause unexpected logic in later strategies. \> The order of these advanced strategies - and my inclusion of them in categories 'tough', 'diabolical' and 'extreme' are my personal choice after close study and are roughly in order of complexity. While the logic is different for each, you should be aware that there is considerable overlap in their power to solve in certain situations. For example, X-Cycles are a subset of Alternating Inference Chains. If you turn off X-Cycles the same elimination might turn up under AICs. Since March 2010 I have reworked most chaining strategies to find the best and shortest chains - not necessarily the first one it happens to find. \> All strategies in the list have [links to documentation](https://www.sudokuwiki.org/Strategy_Families), but it's worth describing what the first tests do: Show Possibles (Naked Singles) : For each unknown square we eliminate all possibles where those numbers are known in each row, column and box. This may reveal a single candidate, in which case we have a solution for that cell. Hidden Singles : If a candidate occurs once only in a row or column or box we can make it the solution to the cell. Test 2 : In this test we check for 'naked' [Pairs and Triples](https://www.sudokuwiki.org/Naked_Candidates#NP) . For example, if we have two pairs, eg 3-4 and 3-4 in the same row, column or box, then both 3 and 4 must occupy those squares (in what ever order). 3 and 4 can then be eliminated from the rest of the row, column or box. Test 3 : This test is for [Hidden Pairs](https://www.sudokuwiki.org/Hidden_Candidates#HP) , [Hidden Triples](https://www.sudokuwiki.org/Hidden_Candidates#HT) Test 4 : Naked and Hidden Quads - much rarer but simply extends Pairs and Triples. Test 5 : See [Pointing Pairs and Triples](https://www.sudokuwiki.org/Intersection_Removal) for a full explanation. This test helps us eliminate numbers in rows and columns outside the box. Test 6 : [Box/Line Reduction](https://www.sudokuwiki.org/Intersection_Removal#LBR) . We check the box against the rows and columns that intersect it for each number. If this solver comes up with an error or it can't be solved, first use the Solution Count button to prove it has only one solution. This uses a fast brute-force algorithm to check for all possible solutions. If it's valid, please use the "Email This Board" button to send it to andrew@str8ts.com. I'd be very interested to study examples that can't be solved on this page. \| Solver created on 28-May-2005. This page was last modified on 10-Apr-2026. All code and design is copyright and for personal use only and may not be reproduced elsewhere. [Copyright](https://www.sudokuwiki.org/Copyright) Andrew Stuart @ [Syndicated Puzzles](https://www.syndicatedpuzzles.com/), 2005-2025, [Privacy](https://www.sudokuwiki.org/privacy) \| \| \| \| \|---\|---\|---\| \| \| All Solutions to a Sudoku \| \| \| ![Logo](https://www.sudokuwiki.org/images/sudoA.gif) \| \| \| \| \| Min-lex version: ([docs](https://www.sudokuwiki.org/Sudoku_Min_Lex)) \| \| \| \| By Andrew Stuart, Rui Gonçalves and Jim White (min-lex) \| \| \| \| \| \| \|---\|---\|---\| \| \| Attempting to minimise the number of clues... \| \| \| ![Logo](https://www.sudokuwiki.org/images/sudoA.gif) \| Warning: This may run for a long time depending on the puzzle and appear to hang. Cancel if excessive. \| \| \| \| Removed: Recursed Still Going\! Finished\! \| \| \| \| \| \| \|---\|---\|---\| \| \| Email your puzzle to a friend \| \| \| ![Logo](https://www.sudokuwiki.org/images/sudoA.gif) \| \| \| \| \| Copy and paste the contents of the green box into your email program and send it off. The links contain the puzzle which will load when your friend visits the Sudoku Solver. \| \| \| \| \| \| \| \|---\|---\|---\|---\| \| \| \| Import a Sudoku puzzle \| \| \| ![Logo](https://www.sudokuwiki.org/images/sudoA.gif) \| \| \| \| \| \| Paste in 81 numbers. Zeroes can be dots or other punctuation. This importer can handle noisy formats like grids with lines and dots. As long as there are 81 separated numbers. Any number greater than 9 will be treated as a set of candidates. \| \| \|
Readable Markdown	null
Shard	70 (laksa)
Root Hash	16065194319553459070
Unparsed URL	org,sudokuwiki!www,/sudoku.htm s443