#Advanced sudoku tricks update#
#Advanced sudoku tricks archive#

you can use XY Wing or other strategies instead of guessing. Some of the ones that you are currently solving using guessing don’t require guessing – e.g. What I would like is a simple way to solve these any secrets or is it just guessing again? I will cross these off my list if it’s just gessing takes all the fun out of it. Then there are the really tough ones that don’t even give you that option and I have not determined any way to solve these. You have a 50% chance of solving your first try. The ones that don’t are the ones with two pairs which force you to choose one of the pair (guessing) and then go from there. This usually leaves you with at least one single number, and then you can begin subtracting again. I just fill in all numbers missing from a 9-square, then further subtract numbers existing in rows across and then again down. Please explain just what a “buddy” is.Īt what point does reverse engineering fail? But, r1c2 contains a 9 as the correct answer. In your example, you write that in figure 4, r1c1, r1c2, and r2c9 are “buddies” of the first and last cell of the Golden Chain. Maybe I just don’t understand the definition of “buddies”.

#Advanced sudoku tricks update#

I will translate and update my own website with those techniques. KrazyDad happens to have a good overview. I am currently at a level where I can solve all easy and intermediate Sudokus, but I still have some problems doing the hard ones, so I was looking for Sudoku solving strategies on the web.

Parcival’s Blog » Solving Sudokus Says:.

Unlike those techniques, Golden Chains is a pattern-matching technique (like XY-Wing), and does not feel so much like a fishing expedition, or guessing. The technique is a generalization of XY-Wing, and solves many (but not all) of the same puzzles that can be solved by other advanced techniques such as conjugate pairs, nishio and coloring.

#Advanced sudoku tricks archive#

KrazyDad » Blog Archive » Golden Chains Says:.You can follow any responses to this entry through the RSS 2.0 feed.īoth comments and pings are currently closed.ġ0 Responses to “An Index of Sudoku Strategies” On Thursday, September 29th, 2005 at 12:17 pm and is filed under Jim's Projects, Puzzles. It is particularly effective when a puzzle has been reduced to a lot of squares containing only 2 possibilities. I have successfully used it to solve a number of my ‘super tough’ puzzles. The technique is a generalization of XY-Wing, and solves many of the same puzzles that can be solved by other advanced techniques such as conjugate pairs, and coloring, but it does not feel as much like ‘guessing’ as those other techniques. UPDATE: Eduyng Castaño wrote to me about a technique he has discovered called Golden Chains (pdf). I find the various coloring/colouring and tabling methods to be too work-intensive for human use – they really make more sense for computer solvers, but sometimes they are the only methods you can use to solve a really hard puzzle.įinally, Michael’s Mepham’s Book of Sudoku contains an excellent 10-page introduction with various solving strategies, in addition to numerous puzzles. These strategies are especially good for solving the Tough and Super-Tough puzzles I offer here. I’ve found the XY-Wing and XYZ Wing patterns occur much more frequently, and are good weapons to have in your solving arsenal. The remaining strategies don’t come into play until the Tough puzzles.Īlthough the XWing (and Swordfish) patterns are easy to spot, statistical analysis shows they do not occur very often. The first 6 methods listed above (Naked Single thru Hidden Subset) are sufficient to solve all the “Easy” through “Challenging” puzzles I provide on this site, and most easy/medium newspaper puzzles. The Sudoku Strategy page explains most (but not all) of the simpler “pattern-matching” techniques. I have not yet found a single website that explains all of these techniques in one location, so I thought I’d provide some links to the various websites where I discovered these techniques. I’ve now learned a number of methods for solving tough Sudoku puzzles by hand, including X-Wing, Swordfish, Jellyfish, Squirmbag, Turbot-fish, XY-Wing, XYZ-Wing, Conjugate Pairs, Bowman Bingo, Simple Coloring, Super Coloring and Tabling. Unlike games of luck such as card and bingo games, guessing is never required. Sudoku is a game of pure logical deduction, just like Kakuro and other Japanese number puzzles.