I still don't know what I am doing. Why do I need to enter a subject when it should just be a new entry under my original Subject?
I only checked to see if anyone had posted a reply this evening as I really didn't expect any. It looks like you replied within half an hour!
Honestly, I have solved about 100 Very Hard puzzles from the Su Doku program but I am STILL stuck on this one.
The processes I use are as follows:
Enter all possibles (referred to as candidates I think). This is the first step and shows up any immediately obvious definites.
Directional Deleting. I think this might be referred to as eliminating candidates. For example, if a 4 in grid X has to be in row Y then it cannot be a candidate elsewhere in row Y.
Pairs. If a couple of numbers are only candidates in 2 cells within a grid, row or column (GRC) then those cells can ONLY contain those numbers.
Triples. Like pairs but 3 numbers and 3 cells.
Unique doubles. The official term is X-something and is the 2x2 version of the swordfish technique (I think). This is where a number can only be in 2 positions in 2 rows/columns, ... You know what I mean.
I have looked for all these techniques in this puzzle, including grid 8 (which I presume is the middle-bottom one).
Out of interest, a work colleague told me of an on-line solver today at
http://www.sudokusolver.co.uk/step.html. This can't solve the puzzle without guessing.
Anyway, please just tell me what I can do in grid 8.
I apologise in advance if it is something that I do know (i.e. one of the techniques above) but I do get a sort of "Su Doku blindness" every so often. In the early days of the puzzles appearing in The Times, Wayne Gould offered a personal service where if you emailed him the puzzle in ".sud" format, he would give you the next move. I used Wayne a few times and every time the solution was something that I knew. I felt stupid but it did give me the confidence to solve all the puzzles since. That was until a couple of months ago when I got REALLY stuck for the first time and I gave up doing the puzzles. It was my Dad who got me going again but now I am stuck again and am really starting to lose faith.
Off this topic a bit, have you tried the Samurai Su Doku puzzles in the Times on Saturdays? I have only seen the ones from 4 and 11 June. The 4 June one wasn't too difficult but it took me about 70 minutes against the guide time of 55 minutes. The 11 June one however took me virtually 3 hours (target time of 85 minutes). If you have seen these, how long did they take you and are you going to enter the national championships?
Well that was quite a long entry. Hope I haven't bored you (if you have even seen it).
Regards
Gareth
It is not hard at all. If you have tried all techniques but it yield no solution, you needs a smart fifty fifty assumption. Let's look at the first box in the third row from the top to find all possibility. You have two choice: 1 or 6. Pray and pick one number and start from there. I pick number 1 and I can play on and on until I finish the game. When I pick the 6, I have error on the first row at the third box on the right (I need number 4 but it contradicts with number 4 on the second box). It tells me that number 6 is a wrong choice.
