Here I review five preselected puzzles from Xaq Pitkow’s 25 Super Grand Master collection of 50 in his Sudoku, Vol. 5.  Only one of five clearly ranks as extreme, above the spotty Grand Master collection just reviewed.  I detail this one, SGM  10 ,  to point out the LPO support of Medusa coloring.  Two  other advanced level SGM puzzles are highlighted in the next post, as examples of advanced coloring.

I selected only five for review, not wanting to cover so much of the limited collection. The review table tells the story:

The basic trace of SGM 10 was simple enough for the 1-D format. Yes , that’s a naked quad in c4.

I’ll skip the usual line marked grid, because it’s all there in this one.  The 358 wing is definitely advanced level, requiring a forcing chain to attach the 35 wing.

Nothing further on the bv scan or X-panel. A blue/green cluster was started, but the clouds of 3- and 8-candidates hems it in.

This imbalance leaves six numbers sparse enough to be eligible for LPO conflict analysis, but ahead of that in the order of battle is a second cluster .  The imbalance also creates a wealth of slinks.

The second cluster spreads into the 9 patterns, and a 3-candidate is trapped.

More decisively, the 9 slinks deliver a quick rebuttal of blue.  Blue implies orange and not orange.  You can’t get away with that.

But wait. Even without blue, there is that 9 bv partner that is asserting the same thing. It must go as well.

When the debris is cleared, the candidate imbalance rewards us with the longest effective remote pair I’ve ever encountered.  Six 38 bv, the end bv proving orange.

You can see the rest from here.  The naked pair NEr2np34 solves one end, and the 38 pathways are all solved. The 34 ducks are also on this row.  Its over.

The review table reports plenty of action in SGM 20. Want the thrill of discovery for yourself before I show it off next time?

Go for it!