The New Sudoku Players' Forum

[DonM]

How is it possible to resist the call of the cell r7c8

So, the simplest "solution" : 8 Singles; r7c8=1or2->contradiction :=> r7c8=5; ste.

JC, I've been taking a look at this puzzle and didn't hear r7c8 calling out to me.

r7c8 contains 3 candidates belonging to 3 bilocals (1r72c8,2r7c82,5r78c8).
It calls therefore the attention before the 2 solutions of B4R4 and the chain snippet of bilocals in R1 as a starting point to the analysis of the puzzle (SteveK's ~first empirical rule).

How did you come up with r7c8=1or2->contradiction? (ie. what chains were used?).

No chain(s) needed in the phase of analysis of the puzzle, like with any kind of coloring such as GEM, RGT, ...

I ask because a) Leren referred to it as a 'single-move' solution

The conséquences of r7c8=1,r7c8=2 and r7c8=5 have to be analyzed together independently of the fact that they could end up in a contradiction, solution.

and b) the alternate solution required relatively complex network moves.

Once such a phase is finished, whether the puzzle is completely solved or not, a set of "chains" can be builded according to some predefined properties.
Here, the shortest solution was looked for instead of a so-called "elegant solution" which is almost impossible to do otherwise, at least one of the best ones.

JC, thanks for the reply. I get it now: The statement, 'So, the simplest "solution" : 8 Singles; r7c8=1or2->contradiction :=> r7c8=5; ste'. was simply a general statement to explain the basis for the Kraken moves that followed. I got misled by the combination of the 'OR' that followed (making it seem like the Kraken moves were a separate solution) and Leren's comment that your solution was a 'single-move' which it doesn't appear to be.

To all: In my solving of this puzzle (a rather excellent one- a reminder of the good Extremes from the past), I haven't found a valid simple single move. On the subject of this puzzle, resurrecting a long-standing gripe I have, I have an issue with Denis B's putting solving value judgments of first 'uses very simple rules' and then after revision to the actual puzzle, 'slightly harder' and following with computer-derived solutions. IMO, very misleading to newer manual solvers here who aren't aware that these are almost entirely computer-based methods (ie. nobody that I've ever come across have routinely or on a regular basis come up with manual solutions similar to his printouts).