Sudoku puzzles, in spite of their Japanese sounding name, was originally developed for publication in French newspapers in the late 19th century as a variation of more common magic number puzzles. The puzzle was refined and took its modern form in the United States in the later part of the 20th century, and became a world-wide phenomena after computer generated Sudoku puzzles became common around 2004. Killer Sudoku is a fun number puzzle in the family of Sudoku puzzles. There’s a common opinion that even though its name contains the word “killer”, it is actually easier than the classic sudoku. Well, not if you play a hard Killer Sudoku. Having a social conversation is a complex mental task: We must listen, remember what the other person has said, think of what we want to say next, and pay attention to nonverbal and emotional cues. Talking is such an effective brain-booster that one study at the University of Michigan saw improved working memory among subjects who engaged in a single 10-minute conversation. 4) Learn something new. The blue lines indicate that the row or column has a 1 within it. The red box shows its location within that row or column. As we can see here, there is only one proper space for 1 to go.

These three constraints, that a digit not occur more than once in a row, column or square, make up the basic rules of sudoku. Strategies for Solving SudokuThat's right - in Labyrinth puzzles you need to create a valid maze on a square grid. You're given a set of Hanjie clues which give you the length of the various wall segments in the square maze. It's a long time since I solved one and I don't have a copy handy, but I seem to remember that you need to find a maze with a single path solution that covers every square of the grid. (So not really a maze at all - more a very windy path!). The interest comes from combining Hanjie-style solving with reasoning about keeping the maze all connected together, so it is a little bit like Slitherlink in that respect I suppose. They're quite fun, so long as you don't mind something a little fiddly since you're solving two things at once - the walls and the maze solution, and both involve drawing lines so you need to distinguish between them carefully (and your 'not here' markings) as you go. (It's one of those puzzles where the side of your hand goes grey from all the pencil!) This is "Oldbird" aka Sue (usually post here as Sue but obv forgot myself when replying to this thread).

When we cross out the rows and columns that already have 7 in them, we see the red square has two open slots available in the SAME column. It wasn't always so easy for Sudoku. When US publisher Dell published a puzzle called Number Place in the 1970s, hardly anyone noticed; it was just another humdrum conundrum, destined for obscurity. Salvation came from a most unlikely source: the Far East. In fact, these two rows alone tell us there is only one true slot. And since we must have a 4 in the square, these two rows give us sufficient information to place the 4 in this slot. This allows us to speed up the process by knowing the facts and principles of the situation. If you can use everything you have learned through these instructions, you can solve this puzzle! This will take a little time to complete.In Japan, word-based puzzles were hampered by the complexities of a language that combined different scripts (kanji, hiragana, katakana, plus a dash of rõmaji). This provided an opportunity for puzzles deploying the Western-style Arabic numerals that were generally in use to represent numbers.

Did it work? Now let’s try your method on 4. Find the correct slot for 4 by looking at the other squares for data just like we did for 1, 2, and 3. Speaking of squares, let’s solve one and walk through it. Now keep in mind, every column, row, and square has 1 through 9 in it. So let’s use that to our advantage. First we will find where the number 1 fits. Rule Out Impossible Numbers By eliminating everything that will not fit, we find that we are left with one number with no objections and that meets all three criteria. Where sudoku puzzles get challenging is when there are multiple open positions in a row or column... In these cases you may need to look at more than one part of the puzzle to figure out how to solve the puzzle. Consider a row that is missing digits 5 and 6. If that's all the information you have, you have little to do except guess. However, you could look at the column that intersects one of the blank positions in the row. If that column already has a 5 in it, you know the value that goes in the blank position MUST be 6 because putting a 5 there would violate one of the sudoku rules. This sort of mutual exclusion is a powerful way to filter out possible values in your solution, and with a little practice you can apply it with rows, columns and squares. Not since Rubik's Cube invaded Britain in the Eighties has the country been so transfixed by a new style of puzzle. And while thousands of us opted for the screwdriver approach then, there's no easy way out this time."Take a look at the red slot. Using ONLY the information from the blue square and the blue intersecting row and column, solve the number for this slot.