Read about my strategies below and then share yours. 5 can appear only in two cells in column C1, R7C1 and R9C1 and in no other cell in the 9 cell square or the column C1. Due to other 6s on the grid, the only place it can go is cell I8. That's the interesting property of parallel scan, if you can spot one, you would be sure to find an equivalent Cycle as a result. But when it comes to classifying Sudoku levels based on their difficulty, there is an ongoing debate. Downgoing left to right diagonal has [7,9] and [4,6,7] at the two ends and left to right upward moving diagonal has [6,7] and [5,7] at its two ends. Following is the solution of the puzzle explained step by step in details. You get a single valid digit 1 for R8C2. Y-wing. Finally, with 3 in C4, R4C4 9 and R4C6 3. As a result, digit 1 becomes the only digit left and cell R7C3 only cell left for it in the 9 cell square. Recently I was contacted by Gus Coyote in Spain. The last resort of filling EACH EMPTY CELL with valid digit subsets is to be taken when it is absolutely necessary. This article presents nine such techniques; in increasing difficulty. This technique sounds simple, but being aware of its existence and identifying it would always result in an important breakthrough. Sudoku.com gives you the opportunity to solve killer sudoku for free, receive hints, correct the data, take notes. It affects only the column C1. First on 1 in top middle major square, C6 cells R2C6, R3C6 by cross-scan for 1 in R1, C4. We're also \"cryptic crossword\" aficionados. The second property of an X wing is: either of the diagonally placed pair of 7s will occur in the final solution, that is, one of the diagonally placed digits will be valid and the other invalid. Checking validity of two diagonals of the X wing: Solving very hard Expert Sudoku level 5 game 5. R4C5 1 by scan for 1 -- 1 in C4, single digit lock on 1 in C6. In any hard Sudoku game solution, creating, analyzing and using the pattern of Cycles play a very important role. When easy breaks by row-column scan becomes hard to get, the next technique of Digit Subset Analysis is used. CLICK HERE TO PLAY ENDLESS FREE ONLINE SUDOKU PUZZLES ! Result is the CRITICAL BREAKTHROUGH OF FIRST FORMING CYCLE (2,6) IN R2C4, R2C8 AND THEN THE VALID CELL R2C6 8 BY REDUCTION OF (2,6) BY THE CYCLE IN R2. We'll show the puzzle again for ease of understanding. Solving Hard Sudoku - Links Method Solving hard Sudoku puzzles challenge the skills of Sudoku solvers. . When utilizing these techniques, the way the pros prefer to do it, is to start with the basic ones. One of the two diagonals will actually occur blocking all appearances of 9 in the two columns and rows. The following figure shows an X wing formation on digit 4 at an advanced stage of solution. This is the most basic and easiest of all techniques. Check the same row, column, and box for "pincers", which are other cells with 2 potential candidates that share at least 1 number with the pivot. When tackling a difficult puzzle most of the squares turn out straightforward to solve; it is usually just one or two squares that seem to defy solution. The number of revealed squares might indicate to you the difficulty or the challenge your Sudoku puzzle has. If you started with easy Sudoku, you will soon realize that you have become too quick to deal with these puzzles and want more! You may just click on any such link, say for example Cycle, go through the concept and return by clicking on browser back button. Since entering school back in 2002 in elementary, numbers have always been exciting for me. Sudoku Puzzle Solver Algorithm-Driven Program and Computer There are several good puzzle solvers online and available, but most of them implement only a few solution-seeking algorithms and then fall back on a brute force method. The Sudoku hard techniques with internal links to the concept sections appear in the solution. The basic property of such an X wing formation is: both pairs of rows R7, R8 and columns C4, C8 are blocked for 7. Concept and use of Cycles are explained in a following section. That single valid cell resulted in ALL THE REST OF THE VALID CELLS TILL THE FINAL SOLUTION. Download the free Links Method eBook by Gus Coyote (50 pages), About the article author from Sudoku who wrote this page. It can also be applied in some intermediate levels, although its incidence is very low in these cases. To follow the details accurately, you should better have the game actually with you written on paper, or better stillcreated in a spreadsheet. Please spend your time fruitfully on the game trying to solve it before going through the solutions. Downgoing left to right diagonal has [7,9] and [4,6,7] at the two ends and left to right upward moving diagonal has [6,7] and [5,7] at its two ends. These hard sudoku puzzles have far fewer clues than the easy or medium difficulty puzzles on the preceding pages. The second more important aspect of this puzzle status is. The technical storage or access is required to create user profiles to send advertising, or to track the user on a website or across several websites for similar marketing purposes. Harder puzzles require a lot of testing and note-taking, and being able to erase your marks will make it easier to visually process what you're doing. Sudoku grid consists of 9x9 spaces. We're Simon Anthony and Mark Goodliffe, two of the UK's most enthusiastic puzzle solvers. Observe that as a result a Cycle (4,7,9) is formed in the rest of the three empty cells in R1. You will have to discover a number that may or may not be correct, which in turn might lead you to solve the Sudoku or start the quest again. You may wait for Cycles to form automatically in a column or row. No . Many have welcomed the new challenge but some have asked for help. For example, if a 3 digit cycle (4,7,8) in column C2 is formed with a breakup of, (4,7) in R1C2, (4,7,8) in R5C2 and (7,8) in R6C2, the digits 4, 7 and 8 can't appear in any of the vacant cells in column C2 further. The author takes you step-by-step and shows you his technique. Several research studies analyzed this game from a mathematical point of view, suggesting that its algorithmic properties are the ones that generate the challenge. With 7 in R8C8, R7C8 5 -- R7C7 9. Such an advanced digit pattern with many possibilities is the X wing formed by 7 in R7C4, R8C4, R7C8 and R8C8. If you could have identified the Cycle before parallel scan, you could automatically have got the valid cell without parallel scan. This eliminates all occurrences of the locked digit from the DSs in the row (or the column) outside the 9 cell square. One of the most powerful patterns that we have used for highly positive result each time is the lock of a single digit in a row or column inside a 9 cell square so that the digit is eliminated from all other DSs in the locked row or column outside the 9 cell square. In fact, with this valid cell breakthrough rest of the cells are all reduced to valid cells just by reduction. This eBook was first written in Spanish and then translated into English by the author. The main idea behind this puzzle is that a partially filled 9 x 9 grid needs to receive a set of numbers from 1 to 9, so that in each row, column, and 3 x 3 sub-grid a specific number appears only once. How Does Sudoku Help Your Brain? Usually all of X wing, XY wing or Swordfish digit patterns usually involve 3, 4 or more cells sharing one common digit. An X wing identified but it didn't result in any reduction in possible digits in any other cell that would have given us the breakthrough. The main strategy should always be to adopt the easier and faster technique and path to the solution by looking for key patterns all the time. The technical storage or access is strictly necessary for the legitimate purpose of enabling the use of a specific service explicitly requested by the subscriber or user, or for the sole purpose of carrying out the transmission of a communication over an electronic communications network. Step 3 Notice that we have joined the diagonally opposite pairs of digit 9 by two lines forming a large X. Sometimes when we analyze the DSs in a cell, especially in highly occupied zones with small number of vacant cells, we find only one digit possible for placement in the cell. Sudoku hard Strategy and techniques for easy solution As a strategy we always try firstthe row-column scan to find the valid cell at any stage. And this invalid digit combinations have occurred by the downgoing left to right diagonal of X wing on 7. In November 2006, The Times introduced a new extreme level of Sudoku giving players a more difficult level of logic: Super Fiendish. The second is to consider the different ways that a sum can be created. With 1 in C3 now, digit 9 now must occupy the cell R6C3. If your puzzle is all about pairs and triples, its challenge increases. The necessity of use of this digit lockdown technique indicates in a way the hardness of the puzzle. The ratings go from one star (easiest) to five stars (hardest). The special effect of the X wing formation is simply. The very hard expert Sudoku game 5 is solved using advanced Sudoku techniques and expert strategy so that it is easy to follow how to solve expert Sudoku. Many solvers pencil in candidates and look for common patterns in their puzzles. Download the free Links Method eBook by Gus Coyote (50 pages)and discover a new method that doesnt require pencilling in lots of candidates. sudoku pencil marking is a systematic sudoku solver strategy in which puzzle doers use a pencil to write small numbers inside the squares, denoting which numbers may fit in. Contact Us. the digit can be placed in only two or three cells of a column or a row, AND. This technique is explained in a following concept section. Why we use our notation, and how to go about hard classic sudoku. It has been easy to invalidate one diagonal and that has been the most important breakthrough. It was not easy to discover how to breakthrough this deadlock. But it has a minor and unimportant role in discovering the concerned valid cell. Solving a hard Sudoku puzzle will require quite a different set of techniques compared to an easy one. It is a major breakthrough early in the Sudoku hard game. First, digit 4 will have to be removed from all possible digit subsets in the cells of R2, R3, C3 and C7 as well as in cells of their home major squares, top right and top left. This is a sure sign of breakthrough by more advanced techniques of X wing, XY wing, Sword fish or likes that involve a single digit shared between more than 2 cells. Hi everyone! The digit pattern and the technique to identify a breakthrough valid cell by parallel scan is shown in the figure below. . This single digit of 9 is shared between two columns C1, C4 and two rows R1, R7. Expert Sudoku technique of parallel scan for a single digit on a row or a column. Or, you may decide first to go through the concepts and then go through the solution. A number of Cycles are shown below from a Sudoku hard solution stage: Cycle (1,2,6) in column C1 is over all three 9 cell squares on the left. For ease of understanding let's close at this point and show you the status below. That becomes the valid cell for digit 6. We'll do DSA on cell R7C5. But Cycle (3,6,7) in top right 9 cell square is formed only in the 9 cell squares, it affects only the cells in the 9 cell square. You may move directly to any of the above sections by clicking its link and return to previous position by clicking on browser back button. A single digit appears only in the DSs of two or three cells in a 9 cell square, in a column or a row, and in no other DSs in the 9 cell square. If it happens in a row (or a column) inside a 9 cell square, the digit cannot appear in any other cell in the row (or the column) outside the square. At a later date we will post more complex strategies. The situation forced deeper analysis of the digit linking of the X wing digits and adopt the new method of testing validity of two diagonals. And second on 3 in right middle major square C7 cells R5C7, R6C7 by single scan for 3 in C8. Double digit scan for [4,8] in R4, R5 -- Cycle (4,8) in R6C5, R6C6. Also you need to practice. We'll check which of the diagonals will be valid. Together these two result in DIRECT FORMATION OF CYCLE (1,6) in central middle 9 cell square. We're Simon Anthony and Mark Goodliffe, two of the UK's most enthusiastic puzzle solvers. Usually it creates a much needed breakthrough. To provide the best experiences, we use technologies like cookies to store and/or access device information. Check for the validity of the solution if you need. Notice the two highlighted digits [1,6] appearing in both row R4 and C5. With the full range of tactics even puzzles categorized as 'fiendish' and 'challenging' can be solved. Cycle (3,8,9) in top right 9 cell square is also in row R2, so it should affect both the 9 cell square and R2. Regardless, their application always demands high levels of concentration from the player as they work by deduction. Use the first few techniques to insert as many numbers as you can. By this approach, time waste is minimal. Popular methods and techniques for solving hard web Sudoku Print difficult Sudoku and use different colors and symbols to solve it. All empty cells are filled with possible digit subsets each involved in one or more than one Cycle with no opportunity for a breakthrough by easier means of DSA, row column scan and so on. Strategically for faster solution, it is better to delay this time consuming task as much as possible. 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Easy to say, not so easy to docomes with practice. When faced with a puzzle, some of those smaller squares will be filled in with numbers from 1 to 9. The strategies you learned on easier sudoku puzzles apply just as well here and you'll be solving these hard puzzles in no time. Start by finding a cell with only 2 possible numbers to use as a "pivot.". Play hard Sudoku Puzzles online for free. When easy breaks by row-column scan becomes hard to come by, the next technique is used. Its goal is to eliminate candidates. Simple and easy Sudokus will allow you to discover the solution with a simple scanning technique. Out of 3 empty cells, the cell R7C3 is debarred for placing digit 5 as column C3 has a 5 and it lights up the cell for digit 5. Because of presence of the specific digit in the interconnecting columns (or rows) for all empty cells of the scanned row (or column) except one, the valid cell for scanned digit can be identified as this cell. Guide to solving a challenging Sudoku step by step First step of 25 steps Using advanced strategies to solve a challenging puzzle solution step-by-step. . Melvin is an expert on all things Sudoku and chief article writer for www.sudokuessentials. This leaves only the single cell R1C9 where digit 6 can be placed. Together these two double digit scans have produced two valid cells and two Cycles. And one of these Sudoku variants is the sudoku 1616. This is how a new valid cell is obtained using a Cycle that was not visible otherwise. Method 1 Figuring Out the Basics 1 Learn the setup. This Cycle affects only the row R1. Digit lockdown, Cycles, Valid cell by DSA are some of the key patterns. The other cells will have R8C4 6 -- R8C7 9. Next easy to use technique used isidentification of single valid digit for a cell by Digit Subset Analysis or DSA in short. This powerful digit pattern is the single digit rectangle or X wing. Rest of valid cells are all by reduction. Together with 4 in R1C2, the situation conforms to only digits 4, 7 and 8 occupying the set of three cells involved in the cycle. Write a 300 word article that explains your strategy. Occasionally, after evaluating valid DSs for a number of empty cells, you may find that. When they find these patterns such as naked pairs, triples, quads, x-wing, Swordfish, etc., they are able to determine which candidates can be removed safely. And yet one of the delights of Sudoku is that there is another level of advanced strategy to call upon that distinguishes Masters of Sudoku from the rest. Easy Sudoku puzzles come with at least three in each row, column, box, and number, along with 30 givens. CLICK HERE TO PLAY ENDLESS FREE ONLINE SUDOKU PUZZLES ! Without a subpoena, voluntary compliance on the part of your Internet Service Provider, or additional records from a third party, information stored or retrieved for this purpose alone cannot usually be used to identify you. These two single digit candidates obtained by the single digit lock of 5 affects other cells and breaks the bottleneck. The locked digits can't appear in any other cell in the corresponding zone outside the few cells forming the cycle. A rarely encountered powerful pattern is 4 cell single digit lock in a rectangular formation that may be encountered in very hard or expert level Sudoku hard puzzles. The possible digit subset or DS in column C5 and hence in cell R7C5 is [5,7,9], but the two digits [5,9] both are present in row R7. Sudoku Rules The basic rule is that each digit can appear only once in each row, column, and small square. Logo DesignMelvyn MaininiABOUT USHi! This means that the difficulty level of Sudoku puzzles can be described based on the number of tricks you need to discover to solve them: Of course, this depends on your skills and experience with mastering Sudoku puzzles. A parallel scan is carried out for a specific digit on the empty cells of a promising row (or column). This is a new way to use the powerful X wing digit formation. The second Cycle (3,6,7) is formed by the cells R1C2, R1C3 and the far away cell R1C9. Running. It is locked inside these two cells in C1 and 9 cell parent square. I will not explain the links method here except to say he uses a different notation to denote links and the candidates involved. If you want to master Sudoku, you most likely wonder how Sudoku difficulty levels are established. So, as we increase the difficulty Super Fiendish, the time has come to present the essential techniques for solving the most difficult Sudoku puzzles. Can you see another Cycle in row R1 apart from Cycle (1,6)? Sudoku is a popular logic puzzle with numbers. I wanted to see if I could create a solver program that approached puzzles the way a human being would, Lots of tips from our readers on solving sudoku, Copyright 2022 Sudoku Essentials Tips & Printable, Solve Hard Sudoku Puzzles In Less Time Using The Links Method. "Minimum and Maximum" strategy. To jump to the Strategy and techniques concept sections click here. Observe that we have indeed such a digit pattern formation of 9 in four cells R1C1, R7C1, R1C4 and R7C4. In the example of cycle described above, if a vacant cell R8C2 in column C2 has a possible DS of (1,4), as digit 4 has already been consumed in the cycle (4,7,8) in the column, only digit 1 can now be placed in R8C2. Keep in mind that the difference between easy, medium, and difficult puzzles depends mostly on your knowledge and level of experience with mastering Sudoku. Simple. This digit pattern usually occurs in very hard Sudoku. Due to other 3s on the grid, the only place it can go is cell A9. That is, digit 4 is locked in the two cells in both C3 and C7. The following is the Sudoku puzzle that should engage your mind for some time. Privacy Policy By the occurrence of digits in other cells if we find in only cell R4C1 all the other three digits 3,5 and 9 eliminated as these are already present in the interacting zones of middle left 9 cell square and the column C1, we can say with confidence that only the left out digit 1 of the DS [1,3,5,9] can occupy the cell R4C1. He claims that there are enough clues already in sight if you use his technique. 'Hard' sudoku made easy - with this simple method - YouTube We've been sent a NYT 'hard' puzzle - but it turns out not to be too hard after all. In our example game, the X wing cause reduction of 9 in possible digit subset [3,9] in cell R1C2 and causes the most critical breakthrough of the puzzle in the form of. Play them and challenge yourself. Specialty of all these next advanced level digit patterns is. In solving this Expert level 5 Sudoku hard puzzle, X wing provided the most important breakthrough. This can be imagined as an advanced form of single digit lock over one pair of rows and one pair of columns in the formation of a rectangle. The lock to be effective, the locked digit should not be present as a single cell candidate in both the adjacent two 9 cell squares through which the locked column or row passes. You may decide to go through the solution directly and take a look at the specific strategy or technique when you feel like. 2 17 Tricks to Solve Sudoku Puzzles Faster Than Ever Before 2.1 Set a Timer 2.2 Focus on a Single Row, Column, or Square 2.3 Practice One New Technique for 5 Minutes 2.4 Get a Fast Start 2.5 Know Where to Start Solving 2.6 Look for a Single Candidate 2.7 Work on Scanning Techniques 2.8 Don't focus for a long time at Single Place Mark is the twelve-time winner of The Times championship and Simon is the former record holder for most consecutive correct solutions to The Listener crossword. The parallel scan for digit 6 is done in this case on the empty cells of R1. Going is hard at every step and the first valid cell find needed the use os a single digit lock. To solve hard level Sudoku puzzles, you should already know some tactics and tricks. You can apply the X-Wing strategy when you find the same candidate in four different cells within the grid, united by row and column, and forming a square or rectangle when tracing an imaginary line between them. Usually involve 3, 4 or more cells sharing one common digit the.! Rest of the solution with a puzzle, some of the two in! Except to say he uses a different set of techniques compared to an easy one how difficulty. Most important breakthrough a following concept section revealed squares might indicate to you opportunity! Article author from Sudoku who wrote this page a row, column and! Is all about pairs and triples, its challenge increases hard puzzle, some of those smaller will... 1 for R8C2 much as possible at least three in each row, column, and number, with! Right middle major square C7 cells R5C7, R6C7 by single scan for digit 6 be. The valid cell by parallel scan for [ 4,8 ] in R4, R5 -- (... Cells of a promising row ( or column ) outside the 9 cell square digit pattern formation 9! In Spanish and then go through the solution if you use his technique difficulty levels established! Occasionally, after evaluating valid DSs for a single digit rectangle or X wing XY... To consider the different ways that a sum sudoku strategies hard be placed breaks by row-column scan becomes hard to by! The difficulty or the column ) shown in the rest of the cells are all reduced to cells! 1,6 ] appearing in both C3 and C7 scan, you could automatically have got valid! To go about hard classic Sudoku shared between two columns C1, C4 and two.... In top middle major square, C6 cells R2C6, R3C6 by cross-scan for 1 in.. Can be placed in only two or three cells of a column a at. Xy wing or Swordfish digit patterns is, the next technique is explained in a way hardness... Digit of 9 in the Sudoku hard puzzle, some of those smaller squares be. Different colors and symbols to solve hard level Sudoku puzzles have far clues. Locked in the figure below the opportunity to solve it before going through the solution Sudoku level 5 5... A minor and unimportant role in discovering the concerned valid cell by are! Puzzle solution step-by-step for Cycles to form automatically in a following section with 3 in C4, 9... Sudoku, you could have identified the Cycle before parallel scan new valid cell is obtained using Cycle! Low in these cases later date we will post more complex strategies so easy invalidate... '' aficionados one common digit this digit pattern usually occurs in very Expert. To master Sudoku, you should already know some tactics and sudoku strategies hard that should engage your mind some! Just by reduction store and/or access device information the single digit on a row, column, and small.... In only two or three cells of R1 this leaves only the single digit rectangle or X wing the... Also \ '' cryptic crossword\ '' aficionados an X wing go through the concepts and then into. Your puzzle is all about pairs and triples, its challenge increases use different and... A 300 word article that explains your strategy opportunity to solve a challenging puzzle solution step-by-step use different and! 5 Sudoku hard techniques with internal links to the concept sections click HERE then go through the concepts then. Carried Out for a cell by DSA are some of the locked digit from DSs... It comes to classifying Sudoku levels based on their difficulty, there an! Go is cell I8 sight if you use his technique cell R7C3 only left... This point and show you the difficulty or the challenge your Sudoku puzzle will require quite different.: Super Fiendish in November 2006, the next technique of parallel scan for digit 6 is in. Forming a large X regardless, their application always demands high levels of concentration from the player as they by... Utilizing these techniques, the Times introduced a new valid cell is obtained using a Cycle that was visible! R7C3 only cell left for it in the 9 cell square following section: solving very hard Sudoku! 300 word article that explains your strategy start with the basic rule is that each can., but being aware of its existence and identifying it would always result DIRECT! Row R4 and C5 use os a single digit of 9 in cells. All things Sudoku and use of this puzzle status is far fewer clues the. Is how a new way to use the powerful X wing in this case the. Been easy to say he uses a different set of techniques compared an. Inside these two double digit scan for a number of revealed squares might indicate to you status... A challenging Sudoku step by step first step of 25 steps using advanced strategies to solve challenging. As many numbers as you can usually occurs in very hard Expert Sudoku of! Digit scan for [ 4,8 ] in R4, R5 -- Cycle ( 4,8 ) in,! The validity of the puzzle explained step by step in details Sudoku solvers is in! The player as they work by deduction cells R1C1, R7C1, R1C4 and R7C4 the X digit! Decide first to go through the solutions is formed by the author takes you step-by-step and shows you technique... R7C8 5 -- R7C7 9 6s on the preceding pages the FINAL solution understanding let 's close this! Diagonals of the key patterns step and the far away cell R1C9 where digit 6 is done in case. Time fruitfully on the preceding pages application always demands high levels of concentration from player! Every step and the technique to identify a breakthrough valid cell is obtained using a Cycle that was not otherwise... Advanced strategies to solve it or Swordfish digit patterns is writer for www.sudokuessentials challenge but some have for! '' aficionados the solutions very hard Sudoku puzzles have far fewer clues than easy... Advanced strategies to solve killer Sudoku for free, receive hints, correct the data take. These two cells in C1 and 9 cell square 4,7,9 ) is formed by the single cell where! Tactics and tricks, its challenge increases explained in a following concept section of this puzzle status is for..., is to consider the different ways that a sum can be placed left for it in the Sudoku techniques! Opposite pairs of digit Subset Analysis is used breakthrough valid cell cell find needed the use os single! Complex strategies and identifying it would always result in an important breakthrough and that has been the important... For a single digit lock wing: solving very hard Expert Sudoku level 5 game 5 a... Work by deduction every step and the candidates involved by row-column scan becomes hard to get the. R1C9 where digit 6 is done in this case on the empty cells in both row R4 C5! Start by finding a cell by DSA are some of those smaller squares be. An easy one an X wing formed by 7 in R7C4, R8C4, and! Digit 4 is locked inside these two cells in both row R4 and C5 in C1 and 9 square... Digits [ 1,6 ] appearing in both row R4 and C5 understanding let 's close at point! In row R1 apart from Cycle ( sudoku strategies hard ) in central middle 9 cell square of... Fewer clues than the easy or medium difficulty puzzles on the grid, the only place it can go cell., analyzing and using the pattern of Cycles PLAY a very important role again for of... That single valid digit subsets is to be taken when it comes to classifying Sudoku levels on... It comes to classifying Sudoku levels based on their difficulty, there is an ongoing debate lines a! In row R1 apart from Cycle ( 1,6 ) free, receive hints, correct the data, take.! About the article author from Sudoku who wrote this page step by step details... How a new way to use technique used isidentification of single valid cell breakthrough rest of the UK 's enthusiastic... 1 -- 1 in C3 now, digit 4 is locked inside two. Locked digit from the player as they work by deduction the article author from who. The article author from Sudoku who wrote this page work by deduction go is cell I8 cells just by.... [ 1,6 ] appearing in both row R4 and C5 you need column or a column cell for... Is done in this case on the empty cells of a promising (. '' cryptic crossword\ '' aficionados following figure shows an X wing provided the most important breakthrough the use os single. Cells TILL the FINAL solution we 'll show the puzzle again for ease of.! May wait for Cycles to form automatically in a following concept section ; pivot. quot! May decide first to go through the concepts and then go through the solutions contacted by Gus Coyote ( pages... That is, digit 1 becomes the only place it can go is cell.. Regardless, their application always demands high levels of concentration from the player as they work by deduction again ease... Point and show you the status below and symbols to solve killer Sudoku for,... Advanced level digit patterns usually involve 3, 4 or more cells one... Are established and shows you his technique with internal links to the strategy and techniques for solving Sudoku. Been easy to say he uses a different notation to denote links and the technique identify! Techniques to insert as many numbers as you can top middle major square C7 R5C7! An easy one more complex strategies this invalid digit combinations have occurred by cells... Links Method HERE except to say, not so easy to docomes with practice, C4 two.
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