Reviewing James Forest’s Classic Sudoku


This post presents a Sysudoku solution of the Classic 24, from James Forest’s Book 30. We’ll do every 24th Classic. The first suggests an easy basic and an interesting diversity of advanced methods.

The bypass fills the East boxes with 20 placements, including naked pairs and two immediately resolved 3-fills.

How many UR signposts are there among the naked pairs in this line marked grid?

Out of five naked pairs, three possible UR’s call for a closer look, for Type 2b.

The same bv are also covered in an unproductive scan for Sue de Coq.

 

 

 

 

The UR is there.

On the bv map, no ANL, but the single i471-wing defines a toxic set.  No victims, but we can  leave the toxic set markers on the grid copies, as we move on to the X-panels.

 

 

 

 

The 4-panel closes Classic 24 out with a finned swordfish. 4r6c1 is the fin, and the removal of 4r4c2 in the fin box brings in C4 and the collapse. It turns out that two of the toxic set members are true.

 

 

 

 

 

Next time, James Forest’s Classic 48 will carry us further along. Can you say just how far?

The Guide pages on the Unique Rectangle and AIC Building are updated.

 

 

 

Advertisements

About Sudent

My real name is John Welch. I'm a happily married, retired professor (computer engineering), timeshare traveling, marathon running father of 3 wonderful daughters and granddad to 7 fabulous grandchildren. The blog is about Sudoku solving. It covers how to start, basic solving to find candidates efficiently, and advanced solving methods in an efficient order of battle. It is about human solving methods, not computer solving.
This entry was posted in Advanced Solving, Puzzle Reviews and tagged , , , , . Bookmark the permalink.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s