I was very tempted to put Naked Triplets in the title for this post after seeing the traffic that “Naked Pairs” generated. I can’t imagine why there would have been such a boost….I leave that as an exercise for the reader.
Naked Triples (and quads) is another sudoku technique that will help you clear out the grid on your way to mastery as you learn how to play sudoku. It builds on the idea of naked pairs, where you found just two cells in a house, containing exactly the same two candidates.
For naked triples, you should look for three cells in the same house containing the same three candidate or a combination of those candidates….read that last bit again closely. I have highlighted two sets of naked triples in the diagram below.
In the centre box, you can see the most obvious example of this technique. Three cells, all containing exactly the same three candidates 2,5 and 9. In the second case, in column 6, the candidates are 1,2 and 5 but you can see that two of the cells do not contain all candidates.
In fact, I have found that this is more often the case than the first one. My own personal favorite is where you end up with three pairs of values that “cycle” round the triple. So, for example, you may see 1,3 then 3,5 and finally 5,1 – looping round to join up the triple.
Now that we have the triples, we can immediately remove the candidates 2 and 5 from the other cells in the middle box, leaving just 6 and 8. It is a shame in this case that the two triples help us with exactly the same cells in the middle box.
A naked quad builds again and has 4 candidates in 4 cells all the same (or subsets thereof!). I tend to find that once you get to naked quads, the rest of the house is already completed and so you gain very little but bear it in mind for those rare cases. In the diagram above you can see a naked quad in box 9 and sure enough, the rest of the values are filled in.
See if you can spot a naked triple in a harder puzzle this weekend….if you read the Sunday Times, I will be interested to hear your experiences.
That doesn’t help me solving the sudoku. I have been playing sudoku for quite a while and I have become very good at it. I don’t (and I cannot) do the technique of filling up all the possible values in each square…that rather confuses me. Lately, I have been looking at the “expert” level…but I have trouble solving it. I have looked everywhere for some one to help me…but so far, I haven’t found anybody. I have looked at your clues…but I find them incomplete…. Is there something I am missing?? Could you help me solve my puzzles?? Thank you
Hi Tygrys, can you give me any more clues as to where you get stuck? With the full set of techniques on this site, you should be able to solve most puzzles.
I realise that I haven’t covered the absolute top level of techniques on here (yet!) but almost all of them need you to spot patterns of cells and candidates. I think that if you can do that without filling out possible candidates, then you have a phenomenal memory.
Hey, just a friendly correction: your cycle, if you had 1,3 and 3,5 and then 5,3 (which is what you put) then the 3,5 and 5,3 would become naked doubles. But, if you had 1,3 and 3,5 and 1,3,5 then that would be the cycle you are referring to. Just thought in case someone got confused you would want to change that 🙂
What can I say? Brilliant catch….I’ve read that text many times and never even spotted my mistake. Corrected now.