KDST 585 Favors the Bypass and Coloring

In spite of a big bypass, Krazydad Super-Tough v.5, b.8, #5 requires some work. An extensive XY railroad looks good, but a comparison with Medusa coloring favors the latter. This brings an opportunity to show unusual coloring resolutions, one involving dead fish.

In a quick bypass, starting with two 3-fills,  KDST 585 fills the second one as an effect of the first one.

Basic ends with a naked quad and three more bv.

Down at the railway station, a nice loop (black) and two ANL (red) collect more bv. There is an interlocking nice loop around two more bv, but it makes no more removals. We could use the interlocking loops for coloring, which looks inevitable anyway.

After a little follow up

We do that.  The nice loops would have generated most of the cluster, but not the 9 removals.

Two full color traps, and the new bv brings expansion.

The expansion produces a  boyfriend trap. 9r1c3 is caught in a cell with the wrong color. It loses regardless of which is true, girlfriend blue or guilty companion green.

The new naked pair removes 3r9c3, and we get a super tough cluster to resolve.

One route is to work on the cluster directly, with lite coloring.  The first probe works. 2r2c8 is blue lite, trapping 2r9c8, making 1r9c8 green, trapping 1r2c8, confirming the blue lite 2 and therefore, confirming blue.

Another route is to use an independent means to removing or confirming a blue or green. The 3-panel has a dead swordfish and a dead jellyfish, and the finned 3-wing here, with a victim in the same box as the fin, 3r2c9.

The expansion puts green 3r1c9 in with green 9r1c9, another boyfriend trap wrapping green, and KDST 585.

Just two more Super-Toughs, with 595 next. Look it up on KrazyDad.com.

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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