What is a link in a Sudoku puzzle? A Sudoku link is a logical relationship.  Links are building blocks used in advanced puzzle solving techniques.  Links are most used in chaining and looping techniques such as Remote Pair, X-Chain, Turbot Fish, X-Chain Variants (2-String Kite, Skyscraper, Empty Rectangle), XY-Chain, Nice Loop/AIC, Group Nice Loop/ AIC, […]