Wex 431 ALS_XZ, 3-BARN, Merge Wrap


One 3-fill fails and one succeeds in a productive bypass, then there are alternatives to two unlikely ALS_XZ in line marking.

Beeby finds ALS_53 and ALS_67 as line marking ends. The latter is duplicated by a regular XYZ-wing.

An AIC ANL is easier than the oversized ALS in the ALZ_53, and the 697-wing is also a 3-BARN, a Bent, Almost Restricted 3  cell region containing 3 values.

The removals produce

and enough slinks for two clusters. The XY ANL that is going to expand the red/orange cluster is also a 3-BARN.

Before the expansion, the 8’s in c3 show the bridge

not(red and green) => orange or blue.

The expansion will produce an orange and blue slink in c3, making orange and blue  opposing colors in the merged cluster.

Now red and green 8’s in c3 trap 8r1c3.

Let’s make it blue/green,

Beeby maps out an AIC ANL through the cluster to wrap green, or we can take the shortcut slink from blue 1 to green 7.

Blue forces SE1 and the collapse.

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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