Tag Archives: Stefan Heine

Beeby on Heine’s ultrahardcore 3

Posted on July 14, 2020 by

This post highlights several moves from Phillip Beeby’s solver, which are alternatives to those appearing in the five earlier posts on Stefan Heine’s ultrahardcore 3. One result is a solution without the second blue green trial, left as a project … Continue reading →

Posted in Extreme Solving, Heine, Puzzle Reviews | Tagged , , , , , , , | Leave a comment

Readers Solve Ultrahardcore 3

Posted on July 7, 2020 by

This post returns to the Stefan Heine’s utrahardcore  3 solution path just before cell and unit forcing chains. It turns out that an immediate coloring trial reaches a solution without them. Then we report how two Sysudoku readers solve it … Continue reading →

Posted in Extreme Solving, Heine, Puzzle Reviews | Tagged , , , , , , | Leave a comment

Ultrahardcore 3 Falls to Coloring Trials

Posted on June 30, 2020 by

This post reports coloring trials that gain the solution after forcing chains when Sudokuwiki gives up.   This includes an example of a grid diagram illustrating the route to contradiction in a breath first trial trace. Then we close with a comment  … Continue reading →

Posted in Advanced Solving, Heine, Puzzle Reviews | Tagged , , , | Leave a comment

Ultrahardcore 3 Schlagt Forcing Chains

Posted on June 23, 2020 by

In this post, we continue with Sudokuwiki into forcing chain methods, and their relevance to the ultrahardcore theme. Sudokuwiki stalls, as Stefan predicts.  Then we fashion a trial for a logical, but practical outcome. On the grid after the red/orange … Continue reading →

Posted in Extreme Solving, Heine, Puzzle Reviews | Tagged , , , | 2 Comments

Cell and Unit Forcing Begins in Ultrahardcore 3

Posted on June 16, 2020 by

This post reveals yet another way to start a boomerang, and reconsiders the practicality of Andrew Stuart’s Cell  and Unit Forcing Chains, this time facing an ultrahardcore right page. We get to a choice between Sudokuwiki and a coloring trial … Continue reading →

Posted in Extreme Solving, Heine, Puzzle Reviews | Tagged , , , , , , , | Leave a comment

Utrahardcore 3 Lifts Off

Posted on June 9, 2020 by

The review of Sudoku ultrahardcore 1 right pages, a separate collection from (and tougher than) its left pages, begins with number 3, shown here post before last.  In this post, we follow Sudoku Basic and the Andrew Stuart’s Sudokuwiki solver … Continue reading →

Posted in Extreme Solving, Puzzle Reviews | Tagged , , , , , | Leave a comment