The New Sudoku Players' Forum

by **Mauriès Robert** » Sat Apr 18, 2020 7:15 am

Hi Eleven,

eleven wrote:Denis and Robert,
what in your opinion is the nicest step in your solution paths ?

For my part, by hand, I sometimes had a hard time to advance the resolution because some (anti-track) chains required prior eliminations to succeed. For example, the very short and decisive 37th, which I considered as the last possible step, required the elimination of r2c2 candidates (steps 28, 29, 30). And for this, it was necessary to identify the role of the 4b1 pair and to use sets to generate the anti-tracks. These are nice steps. On several occasions, I had to use generating sets to get results (steps 12, 18, 20, 21) . These are also nice steps. What was important was to see the key role of the 6.
Sincerely
Robert

by **StrmCkr** » Sat Apr 18, 2020 8:56 am

here you go an interesting opening move aaals 2RC xz with strong link support completing the 2RC

Code: Select all: +----------------------+----------------------+---------------------+ | 5789 256789 25679 | 4 126 157 | 3 2568 15678 | | 3 245678 24567 | 12568 126 157 | 125678 2568 9 | | 578 25678 1 | 2568(3) 9 57(3) | 25678 4 5678 | +----------------------+----------------------+---------------------+ | 4579 234579 24579 | 569-3 8 459-3 | 2567 1 34567 | | 1 2345 8 | 7 346 (345) | 9 2356 3456 | | 6 34579 4579 | (1359) 134 2 | 578 358 34578 | +----------------------+----------------------+---------------------+ | 2 4689 469 | (139) 5 (1349) | 168 7 1368 | | 45789 1 4579 | (39) 347 6 | 58 3589 2 | | 579 5679 3 | 2-19 127 8 | 4 569 156 | +----------------------+----------------------+---------------------+

Aaals a) 13459 @ R6C4,R5C6
Als b) 1349 @ R7C56,R8C5
Als C) 39 @ R8C4
RC: 4,9
Strong link 3 @ R3C46 to both als A & B & C where by 3 can only be in A or B or C but not all 3.
=> R4C46 <> 3 , R9C4 <> 1,2

Website · by **denis_berthier** » Sat Apr 18, 2020 9:27 am

StrmCkr wrote:...
=> R4C46 <> 3 , R9C4 <> 1,2

Unfortunately, this doesn't change anything for the rest of the solution.

by **StrmCkr** » Sat Apr 18, 2020 9:31 am

Unfortunately, this doesn't change anything for the rest of the solution.

agreed this puzzle is nasty with lots of forcing nets.

Website · by **denis_berthier** » Sat Apr 18, 2020 9:36 am

StrmCkr wrote:
Unfortunately, this doesn't change anything for the rest of the solution.
agreed this puzzle is nasty with lots of forcing nets.

We don't need nets. Only oriented chains.

by **eleven** » Sat Apr 18, 2020 2:03 pm

Thanks for your answers.
I will have a closer look a Robert's later.

denis_berthier wrote:Let me ask you the same question: did you find any interesting step in this puzzle?

I did not spend longer time on that puzzle, just had a look at endless chains of a solver (hodoku) and the solutions presented here.
That's the problem with such hard puzzles. I takes at least a whole day, also with solver's help, to make some deeper analysis. Of course under the many possibilities for the order of eliminations you can arrive at situations, where nice moves are possible. But probably for my taste already totuan made the best of it.
However, since it is much discussed now, i plan to study it closer in the next days.

by **eleven** » Tue Apr 21, 2020 11:50 am

Now i have made my solution. I kept the steps as simple as in the one-stepper puzzles.
From this point of view there was not much to analyze. I just tried to reach a number and make more or less helpful eliminations to get one.
So the solution is very similar to Robert's, not only in the number of steps (37). It also seems, that there is not a big variety in the solution paths made with simple steps. The order may differ, but many steps are similar and also the numbers found, especially the early ones.

Nice steps ? I would not say. For sure i can find nicer moves in 30 one-steppers. Also, after some time, i lost any interest in looking for them, just wanted to finish.

So i think, this kind of puzzles is only of interest, when you are working with complex steps. But i do not have any tools, that could help me for that (e.g. finding multiple backdoors).
In any case, my respect for totuan's solutions was still growing.

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