Returning to more normal value balance, Beeby finds hidden UR and finned fish before a series of ANL and 1-way AIC gets us to coloring. It takes a complex 1-way and an ALS _XV before I take over to resolve one cluster and get expansion traps for a final wrap.
Two 4-fills fail to start Basic and a 3-fill succeeds. Another 3-fill is resolved. One naked single with boxline showed up in line marking.
The boxline removal is 6r7c6 based on confinement of the r8 6’s to the South box.
Then Beeby finds the hidden unique rectangle in which 3r8c8 makes 2 false and the slinks place 2 in the adjacent corners. The wink then leaves 3r7c6 in the opposite corner, leaving the 23 rectangle in which interchanging 2 and 3 gives a second solution.
We superimpose the next finned 3-wing on the grid.
The fin spoils the 3-wing on columns 2 and 8, but if the victim were true, the fin would be removed, leaving the repaired 3-wing to remove it.
Next is a sashimi 7-wing on columns 2 and 7, and a finned 7 swordfish on rows 3, 5 and 9.
With a small blue green cluster started, a series of AIC offer to expand it.
First is a 1-way that found its way into the cluster for an easy ANL.
Then a 1-way from 9r9c5 that ends untypically with a slink. If the starting 9 is not true, then 2r9c9 is. Either way, 9r9c9 is toast.
A second 1-way, starting on 7r5c9 ends the AIC by the script.
The cluster doesn’t interfere with the hidden unique rectangle that it enables.
It does add a bv and a 7 slink to c7, encouraging a second cluster, which offers a red or blue bridge in r3:
The next 1-way triggers a boxline removal 8r6c7, but still no coloring resolution.
With other options closed, I request a complex 1-way. And Beeby delivers a strange one.
The 1-way AIC negotiates the 2-cell ALS 178 and its three groups differently. If 1r1c3 is false, 8r3c3 is false, but in this case, 8r2c2 must be true, making the third group 7 false.
Forward branches create two slinks for the AIC. The removal has no apparent effect until . . .
one more bv leads to an ALS_93 that wraps orange. Blue or green would have been better, but . . .
the blue/green expansion traps 1r9c7, and
The quintuplet takes 9r9c9, and . . .
the expansion trap wraps blue, as a second blue 1 is forced into c7.
The blue wrap leaves a single SE1 in c7, and a collapse.
Next week, we take a short break on the Weekly Extreme review, to return to Antoine Alary’s “most difficult” of the 200 “toughest Sudoku puzzles known to man”. The reason is to help report an alternative solution by a Sysudoku reader, who took up the challenge and independently solved More Extreme 200 using his own order of battle. H
Systematic Sudoku 