Absolutely Nasty Sudoku Level 4

by Frank Longo

Top solvers can try their hand at the One-Sided Gordonian Rectangle; Extended Gordonian Rectangle; Gordonian Polygon; and Alternating Digits. (But they can take comfort in knowing that no more than one will occur in any single puzzle.)

Genres: Puzzles

160 pages, Spiral-bound

First published March 1, 2007

Reviews

[Paul Weiss · Rating 4 out of 5]

Exactly as advertised!

A two page introduction, frankly, is of absolutely no value in helping puzzlers solve anything in this book. The reason for that is extraordinarily simple. The title is exactly correct. The book is all puzzles, straight sudoku, no variations and they're all difficult. They uniformly require one and, frequently, multiple applications of advanced techniques such as:

Crosshatching
Single candidate squares
Single square candidates
Virtual crosshatching
Naked pairs, triples and quads
Row, column and box claims
Remote pair chains
Non-unique rectangles
Bivalue Universal Grave
X-wings, Swordfish and Jellyfish
XY-wings
XYZ-wings
Conjugate Pair Chains
Multi-colouring
XY-chains

There is no instruction in the book at all that would help you with techniques at this level.

Paper quality is excellent and will take multiple erasures. The ring binding is wonderful and allow puzzles on both sides of the page to be solved on a perfectly flat surface. Good job, Mr Longo, and thank you.

Paul Weiss

[Faye Butte · Rating 5 out of 5]

Challenging puzzles