The funster Extreme collection review closes here, with the early departure of the last pre-selected puzzle, Extreme 130. Charles Timmerman’s funster Hard to Extreme Sudoku includes 134 Hard, 134 Very Hard and 134 Extreme puzzles.

Here is the Sysudoku review table for the funster Extreme collection. Every 14^th puzzle was taken, arriving at 130 to finish.

Maybe 130 pulled strings to get a seat in the Extreme gallery. The collection exhibits pleasing variety of advanced methods, and plenty of highlights. These include a finned X-wing in line marking, some Sysudoku firsts in coloring, and several elimination victims by inference chain “seeing”.  I rate it “funster Advanced”, but not extreme. An appropriate level for funstering.

Not much left to do,  but display a basic trace of Extreme 130. Two naked singles on the same line trigger a quick collapse.

Next, and before starting the basic level review of Will Shortz’s Hard Sudoku, v. 1, is a report in two posts on my experiences in a return to Andrew Stuart’s treatment of the ALS node in AIC chains, in The Logic of Sudoku. I followed up his Figure 30.1 example by working the puzzle from the beginning.  The result is the more comprehensive view of the ALS node now in the Guide, as signaled by AIC hinges, and as it is re-used twice for further eliminations.

In case you would like to compare details as usual, and without looking at the first ALS node in Logic’s Figure 30.1, here’s the given grid.

In search of another example, I also worked through Andrew’s challenge puzzle 17 immediately following  Figure 30.1. It provided another ALS node example, but further insight into AIC hinges, for the Guide.