Tag Archives: XY-wing

Brian Challenger’s Super Fiendish 7


The review of Challenger’s Super Fiendish collection opens with a long post, revisiting some advanced methods not seen here recently. Somewhat fiendish is the stonewalling in basic. The bypass gets nowhere, and the hidden triple alone removes candidates. Here is … Continue reading

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Books 3 and 4 In the KD Insane Review


Welcome to 2019 Systematic Sudoku. This post continues on the updated KrazyDad v4 review, with KD Insane 435 and 445. This is a brief report on what you’ll find in the updated posts of August 2013. The review update begins … Continue reading

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Funster Extreme 60 and 74 Go Together


Two brief advanced appearances are reported in this post in review of the Extreme section of Charles Timmerman’s Funster Hard to Extreme Sudoku. In Extreme 60, the bypass starts with a 3-fill and uses them to solve a big wedge. … Continue reading

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The World’s Most Over-Titled Sudoku Book


This post starts the review of World’s Hardest Sudoku Book, tracing Very Hard 25, the only one rated a 1.00. The review will cover the highest rated 10, taking the rating down to 0.90. The lowest of the 200 is … Continue reading

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Decoding Hodoku Chain Notes


This post comments on the first part of the Hodoku “Chains and Loops” page. It reveals the premise dependent view of chains to be based on computer coding, and unsuited for human solving advice. It explains Hodoku’s chain notations as … Continue reading

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Hodoku’s Limited XYZ Wings


In this post reviewing the Hodoku Wings page linked under Techniques, we see how an expert programmer can go wrong in explaining how to recognize where a technique applies and why it works . The omission of irregular wings is … Continue reading

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Wings and Chains With the Gordon Guide


This post reviews the Chapter 9 of Peter Gordon’s Sudoku Guide, entitled Forcing Chains and Grid Coloring. The guidance is very limited, and what there is, promotes guessing as opposed to solving by logic. This verdict is confirmed in the … Continue reading

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