Sudokuwiki Reaches Its Digit Forcing Chain

This post illustrates the power of coloring to employ the strong link network, and again rejects Andrew Stuart’s Digit Forcing Chains?. The post bypasses the Nakamoto Extreme 23 coloring wrap of the previous post, and follows Sudokuwiki AIC building  to the “digit forcing chain” .

Leaving the original Sudokuwiki grouped AIC boomerang 9 without invoking the blue wrap extensions, Andrew Stuart’s solver finds  boomers 10 and 11 incorporating the same grouped slink.




Then comes two rare sights together, a regular XYZ-wing and boomer 12 with an ALS node.








Still counting, a grouped boomer 13 from 2r2c9.









Building on that, Sudokuwiki calls this a digit forcing chain, making 1r5c5  true whether  9r1c3 is true or false.

Picking 9r1c3 is misleading. The same attribution can be made for any other candidate along the loop.


The conclusion actually comes from the loop itself. It is a confirming almost nice loop, an ANL, asserting green.

Next week, Sysudoku Basic and Sudokuwiki advanced for Nakamoto Extreme 43.

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.
This entry was posted in Extreme Solving, Nakamoto, Puzzle Reviews and tagged , , , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s