This post gets left page ultrahardcore 177 to coloring with an interesting Sysudoku Basic and a kraken X-wing accessed with a recently added AIC option.
Stefan Heine’s ultrahardcore 177 makes many left page concessions, but makes a fight of it. The basic trace shows a moderately productive bypass, and a naked triple in line marking.
The naked triple is unusually productive, and
the full grid is graced with two hidden unique rectangles. To unravel them, use the slinks to trace what happens to the rectangles if the removal victims are true.
Beeby follows with a simple ANL out of AIC building. It has three winks in multicell nodes, a string of slinks.
On a rerun looking for alternatives, a necessity for analysis with Beeby, I requested a recently added AIC option, an AIC with X-wing, and was rewarded with this kraken X-wing.
On the 9-panel the X-wing and fin are easily found, but “kraken” denotes a finned fish where the victim is not in the fin box. The AIC is required here to verify that the victim sees the fin, making it a victim. Figure the logic.
On the first run, I didn’t ask for, and didn’t get, the kraken removal.
But its result was duplicated. Instead, a second Simple AIC produces a decisive ANL. In DIY mode, the ANL could have been started as a boomer from 8r4c1 or a 1-way from 8r5c4. The four removals generate four new bv cells, opening the middle for coloring, and generating clue W8 and boxline Wc1.
The cluster traps 6r5c3, and the boxline removes three 9’s.
The blue/green expansion and and cluster exit AIC from green 3 finds an ANL with blue 1r5c2, wrapping green.
Do the follow up for the first grid of next week’s post:
It exposes a moderate puzzle within ultrahardcore 177.
Systematic Sudoku 