The eliminations are similar to the Locked Candidates technique. This is often seen in handmade sudokus, where the maker deliberately builds a consistent flow in the puzzle, with the occasional twists and turns. Wednesday Jan The example on the right shows a Naked Triple in a box: In a naked triple, three cells in a row, column or block contain some combination of the same three candidates. A Swordfish in the columns is usually a little more difficult to spot than one in the rows, but in this particular case, the equal spacing favors the Swordfish in the columns, as we are more accustomed to notice regular patterns. How easy is it to spot a situation that you can use?
This reveals a naked pair containing the candidate values 5,7 in same row. You will get to similar wrong position when you put 8 in column 4. They are marked in red. This is a digit that cannot be in both sets at the same time , because all candidates for the digit in both sets can see each other. When the pivot does not contain 4 or 9, it will contain digit 6.
That allows us to remove the yellow highlighted candidates. The right side has the Naked Quadruple in block 7: Connect the blue candidates and you will see what I mean. Clearly, only the three triple cells can contain the three triple numbers. Though Naked Singles are easy to explain, they are not easy to find in a Sudoku. In this case, R2C5 has 4 candidates. And remove it from all other cells, to normalize:
Stay tuned for more solving techniques Thanks for reading this solving guide all the way to the end. Some cannot see naked singles without pencilmarks. I would like to draw your attention to the cells with candidates for digit 1. Now that we have established that these two green cells cannot contain 7, we can say that none of the green cells can contain digit 7, because it is not possible that some green cells contain a 7 and others not. Currently, 17 is the minimum for 9x9 Sudoku. The other red candidates merely indicate the eliminations caused by this placement. Most of them use one or more strong links that restrict some of the digits, allowing us to eliminate others.