# Guide

The Sysudoku Guide

This is the online version of the Sysudoku Guide. It’s a pyramid of pages. Pages are accessed directly through a drag-and-click menus. Click on a menu link to access the page. Drag right on a on the parent link into a menu of child pages.

“Sysudoku” stands for Systematic Sudoku, a system for solving sudoku number placement puzzles. The Sysudoku system is engineered to take advantage of human abilities to solve puzzles of every difficulty level. For hard puzzles, the system supports templates for universally available office software.

Sudoku is not a math game, The game pieces are digits 1 – 9, but with no numerical properties. They are just familiar symbols. It’s not a logic game either, although “street logic” plays a role in solving. Sudoku is a constraints game, played on a 9 by 9 grid divided into nine 3 by 3 boxes. A set of digits, the givens, are placed on cells of the grid, defining the puzzle. The givens, plus the placements you make, are the clues. No givens of the same value are in the same row, column or box. The object of the game is to fill the remainder of the grid while maintaining the same constraint: no clues of the same value in the same box or line. This guarantees that every row, column and box will contain all 9 values.

This sounds so simple, that if you are a beginner, you may have to try it on a few Sudoku to realize that it takes some kind of strategy to succeed. The pages of this guide explain a single process for human solving of Sudoku puzzles. It’s just that, the harder the puzzle, the further you go in the process. If you are a beginner, you will not need to go beyond Sysudoku Basic/ Sysudoku Bypass to solve most newspaper and magazine puzzles. But then you may want more, and there are plenty of “hard Sudoku” books and sites. With good reason. There is a lot more you can do in Sudoku.

Basic solving generally means identifying and marking the possible placements of values in cells, the candidates. Harder puzzles require this task to be completed for more advanced solving methods. The Sysudoku version makes placements, adds additional information while achieving this task.

If you are an experienced Sudoku solver, the attraction of the Guide pages is to find a consistent, fully explained and documented system of doing Sudoku differently. Candidates are pencil marked differently, and relationships are displayed graphically. Methods are explained with reference to fundamental principles. Spotting guidelines are included. Methods are sequenced logically, around helpful visual tools constructed as needed. A compact tracing system supports complete documentation of the basic solving path. Yes, there is a basic solving path. The ©PowerPoint presentation file is demonstrated to be an ideal tool for recording and sharing complete solutions.

Regardless of prior experience, the best approach is to read through the Guide in the role of a beginner. Rejecting Systematic Sudoku without experiencing it, because it is different, is rather pointless, because the experience is the only point. Start with the Sysudoku Basic page for an overview of basic solving, then settle down with your blank grid and Begin With The Bypass.

By way of introduction to the main pages:

Sysudoku Basic concentrates attention on the basic solving task, and solves most newspaper and magazine puzzles. The beginning phase, the bypass, gets more placements from the fewer candidates. Only the givens, the placements already made, the clues, and the most telling of the candidates, are involved. Then in two more basic stages, pairs of strongly linked candidates are added. Box marking adds linked pairs in boxes. Line marking adds the links along rows and columns, while completing all candidates line by line.

Sysudoku Advanced pages equip you for the hard puzzle collections offered in books and web sites. They provide a plan of attack, with the sequence of actions, why they work, and how to recognize when they apply. The methods are labeled as “advanced”, not because they are complicated, but simply because they depend on having all candidates, and therefore follow basic stages

Both basic and advanced Sudoku are analyzed in these blog posts, usually among puzzles pre-selected for collection reviews. The posts provide very worthwhile examples, especially for those willing to read through traces by filling out grids, and to consult this guide to pin down exactly why each move is made, and to invest in the tools used here to reveal the logic of the solving paths.

Two areas are explored in the blog, but are not yet included in this Guide:

The Sysudoku Trials pages will describe several alternatives to arbitrary guessing when you are stumped by a Sudoku. Here, a trial is the assembly of candidates into true or false sets of candidates and trying one army. Of course, true means “in the solution” and false means “can be removed”. There is even a “breath first” version of the Sysudoku trace to discover if a false army is contradicted in a few moves.

Monster Methods may yet explore logical and humanly accessible techniques for puzzles so saturated with candidates that advanced techniques cannot be attempted. Several monsters have been solved, but only by trials. Sysudoku attempts can be found by Titles/Monster Posts.