Rules: Standard Sudoku rules (insert a number in the indicated range into each cell so that no number repeats in any row, column, or bold region). Some cells are split by slashes; in these cells the smaller number must go above the larger number.
Answer String: Enter the row/column marked “A”, followed by a comma, followed by the row/column marked “B”. Rows are entered from left to right and columns from top to bottom. This example has the key “149567823,356182749”.
(Brief) History of Tight Fit Sudoku: Descended from Sudoku. The idea was first developed by Thomas Snyder for his book Mutant Sudoku, inspired by a playoff puzzle that almost appeared at the second World Sudoku Championship in Prague.
History of this example: This Tight Fit Sudoku was written by Thomas Snyder for the 2009 Czech Sudoku Championship.
Sources for Tight Fit Sudoku: Follow this link for Tight Fit Sudoku puzzles on this website. If you are new to this puzzle type, here are our easiest Tight Fit Sudoku to get started on. More Tight Fit Sudoku puzzles can be found in our beginner-friendly collection Intro to GMPuzzles by Serkan Yürekli and in The Art of Sudoku 2. Other sources (some potentially now out of print) are Mutant Sudoku and the Sit and Solve title Tight Fit Sudoku both from Sterling/Puzzlewright.
Design rules for contributors: A Grandmaster Tight Fit Sudoku will have a unique solution that can be reached by logic alone. Generally, a Grandmaster Tight Fit Sudoku has a symmetric layout of slashed cells, and a symmetric or pseudo-symmetric layout of givens, meaning that the same tight fit cells may contain givens but they could all be “tops” and not have to be rotationally symmetric. Ranges from 1-7 to 1-12 are allowed in the standard 6×6 form.