A Lite Coloring Update of Castillo’s Only Extreme 261


This post is the first of several which update earlier review solutions to include a new guy in town, lite coloring. The earlier posts will be left as they are, except for added links to these updating posts. Instead of direct links, you’ll have dates of the earlier posts. Use the by-month index in the right margin to access them.  You get titles and first lines of neighboring posts.

The first lite coloring update is the post of November 28, 2017 on Castillo’s Only Extreme 261, which ended with a Not-Both trial.

One or both of the 7 terminals of the AIC is true. Also, one of them is green. For a while I used Not-Both trials to extend the slink network, the coloring. Here it would test of both 7’s being green. Here, the trial solved the puzzle.

An update post on Only Extreme 261 of April 30, 2019 showed that all of the 5 patterns leave a green 5 orphan, wrapping green and avoiding the coloring trial.

Without looking below, note your lite coloring on the grid above.

OK, on my lite coloring, the blue lite tree from 7r9c9 follows the path of the AIC, reaching 7r4c7, the uncolored terminal. If blue is true, 7r4c7 will be blue. That’s not enough to extend the cluster along the AIC, with green 7r4c9 and blue 7r4c7, but it’s  similar progress with no trial.

And red is blue lite, everywhere, because if one red is true, all are. With green lite 8r8c8, that gives us a nice set to lite traps.

Now look at the lite tree from 7r1c8. 1r1c6 is blue lite.  Using the grouped wink in the North box, 1r8c6 is blue lite. Using another grouped wink-slink, the r12c6 1-group is blue lite as well. Weird that any of these facts could be applied in a lite trap. But if green is confirmed, it’s all fake news.

Next week, we do a complete update of the 12/19/2017 post on Castillo Only Extreme 347. Originally it was a coloring trial used to illustrate the Sysudoku trial tracing technique. Phil Beeby’s solver finds simple chains to a color wrap with a lite coloring issue. There is also a bypass update featuring prominent use of 4-fills. Interested in trying it out along those lines? Don’t mind if you do.

About Sudent

I'm John Welch, a retired engineering professor, father of 3 wonderful daughters and granddad to 7 fabulous grandchildren. Sudoku analysis and illustration is a great hobby and a healthy mental challenge.
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