Category Archives: Extreme Solving

Extraordinary techniques deferred past advanced ones, because of effort vs. likelihood of success.

The Complex 1-Way in AIC Building


This post is about an AIC building option offered by Philip Beeby’s PhilsFolly.com solver, and how and where it is best applied in DIY solving.  Here we refer to this solver as Beeby and this technique as complex 1-way.  Complex … Continue reading

Posted in Advanced Solving, Extreme Solving, Heine | Tagged , | Leave a comment

Ultrahardcore Review ALS-wings V


This post completes a survey of ALS-wings in the review of Stefan Heine’s ultrahardcore collection. The study was to determine how ALS-wings can be constructed as ALS maps are built. This post covers five more examples in UHC 443 found … Continue reading

Posted in Advanced Solving, Extreme Solving, Heine | Tagged , | 2 Comments

Ultrahardcore Review ALS-wings IV


The survey of ALS-wings in the ultrahardcore review continues, with new wing building situations, another ALS version of the Death Blossom, and an amazing ALS. In this UHC 267 ALS-wing it’s a two box ALS , connected by a column … Continue reading

Posted in Advanced Solving, Extreme Solving, Heine | Tagged , | Leave a comment

Building the ALS-wings of UHC 3


This post begins a review of examples of ALS-wings from the ultrahardcore review. The review will illustrate a DIY strategy for constructing them, that is compatible with the concurrent ALS mapping and ALS_XZ building processes of the previous posts. Ultrahardcore … Continue reading

Posted in Extreme Solving, Sudoku Toolware | Tagged , , , | Leave a comment

An ALS_XZ Wrap Up of UHC 311


This post shows what it means to maintain three three ALS maps. ALS map updates are followed through a series of  ALS_XZ until a decisive coloring wrap on Stefan Heine’s ultrahardcore 311. We are exploring ALS mapping as ALS_XZ scans … Continue reading

Posted in Advanced Solving, Extreme Solving, Sudoku Toolware | Tagged , , | Leave a comment

Scanning the Column ALS and Some ALS Coloring


This post displays the column and box ALS maps, and scans for AIC the columns. The box scans are started, but get interrupted by an ALS coloring expansion. We start with the ALS column map on ultrahardcore 311 . It … Continue reading

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

Building ALS Maps With Suset Tables


This post displays the ALS map for rows of UHC 311, at the moment when the Beeby solver returned the first ALS_XZ. The suset ALS marking and building aid is introduced, and suset tables for rows, columns and boxes are … Continue reading

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

Coloring ALS Value Groups in UHC 311


This post introduces the expansion of coloring clusters by coloring groups by grouped strong links, such as the those between value groups in ALS. This advance is especially significant as we address whether or not to exhaustively construct ALS and … Continue reading

Posted in Extreme Solving, Sudoku Toolware | Leave a comment

Lite Coloring Avoids Trials in KrazyDad 425


This post backs up your lite coloring effort, I hope, on KrazyDad 425. The initial lite trees deliver a cluster merge, and as these grow, lite coloring gives two confirmations and a coloring wrap to finish without trial. The first … Continue reading

Posted in Advanced Solving, Extreme Solving | Tagged , , , , , , | Leave a comment

Pattern Trials Peel the UHC 487 Onion


The ultrahardcore review ends, with Stefan Heine’s 487 giving up a naked single and two skyscrapers, and a jaw dropping complex 1-way, shuts down the solver team. Slicing at it with three onion peeling pattern trials leaves very little for … Continue reading

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