Sudoku Knowledge Base

Learn how to use multi-select mode to quickly mark candidate numbers. This guide covers usage methods, practical tips, and FAQs to double your Sudoku solving efficiency.

Learn about guessing techniques in Sudoku: when to guess, how to guess efficiently. Master hypothesis testing, bifurcation, and other advanced techniques to make guessing a logical reasoning process.

Chain Reasoning Series (1/3): Deep understanding of strong links (exactly one true) vs weak links (at most one true), their sources and properties. Read all 3 parts in order.

Chain Reasoning Series (2/3): Learn chain building methods, alternating rules, coloring concept, and three ways to draw conclusions. Please read Part ① first.

Chain Reasoning Series (3/3): Complete classification of chain techniques - open/closed chains, single-digit/bi-value/mixed chains (AIC), grouped links, discontinuous loops. Final part of series.

Explore the complete history of Sudoku: from Euler's Latin squares in the 18th century, to modern Sudoku design by an American architect, to Japanese naming and promotion. Learn how Sudoku became the world's most popular logic puzzle.