Greater Than Sudoku strips away all given digits and replaces them with inequality signs between adjacent cells. These relational clues - indicating which cell holds the larger value - create an ordering puzzle layered on top of classic Sudoku logic. The result is a refreshing variant that emphasizes comparative reasoning and rewards methodical deduction.
Greater Than Sudoku uses the standard 9x9 grid and follows all classic Sudoku rules. The key difference is how clues are presented: instead of pre-filled digits, the puzzle features inequality symbols (< and >) placed between horizontally or vertically adjacent cells. Each symbol points from the smaller value toward the larger one.
For example, if you see a > sign between two cells, the left cell must contain a larger digit than the right cell. If you see a < sign, the left cell must contain a smaller digit than the right cell. By analyzing chains of these inequalities, solvers can determine the relative ordering of digits within rows and columns, then use standard Sudoku logic to pinpoint exact values.
The variant is sometimes called "Comparison Sudoku" or "Inequality Sudoku." It has been a popular format in puzzle magazines and competitions for over a decade, valued for its clean presentation and the way it forces solvers to think about number relationships rather than specific digits. Greater Than Sudoku appears regularly in the World Sudoku Championship and various online puzzle contests.
Greater Than Sudoku follows all standard Sudoku rules: each row, column, and 3x3 box must contain the digits 1 through 9 exactly once. The additional rules are:
Inequality signs between adjacent cells indicate which cell contains the larger digit. The pointed end of the sign always faces the smaller number, and the open end faces the larger number. Inequalities appear between horizontally adjacent cells within a row and vertically adjacent cells within a column. No pre-filled digits are provided - all values must be deduced from inequalities and standard Sudoku constraints.
In some variations, not all adjacent cell pairs have inequality signs shown. When a sign is absent between two cells, it means there is no direct comparison clue for that pair. Every Greater Than Sudoku puzzle has exactly one valid solution reachable through logical deduction.
Greater Than Sudoku is rated as intermediate difficulty. Although starting with a completely empty grid can feel intimidating, the inequality signs provide a surprising amount of information. With practice, many solvers find that Greater Than Sudoku puzzles are approachable and deeply satisfying to work through.
This variant is ideal for solvers who enjoy classic Sudoku and want to develop their logical reasoning skills further. If you find standard puzzles too focused on spotting single digits and prefer thinking about relationships between numbers, Greater Than Sudoku is an excellent fit. It is also a wonderful stepping stone toward more complex variants like Thermometer and Arrow Sudoku.
Look for the longest chains of inequalities first. If you find a chain like A > B > C > D within a row, you immediately know that A is at least 4, B is at least 3, C is at least 2, and D can be as low as 1. The longer the chain, the more constrained each cell becomes, giving you strong starting deductions.
Pay special attention to cells that are larger than all their adjacent neighbors (local maxima) or smaller than all their neighbors (local minima). A cell that is greater than both its horizontal and vertical neighbors must contain a relatively high digit. If such a cell is in a box where many high digits are already placed, its value becomes highly constrained.
Combine inequality analysis with standard Sudoku elimination strategies. Once you narrow down candidates using the inequalities, apply techniques like naked singles, hidden singles, and box-line reduction to resolve cells. The combination of relational logic and traditional Sudoku reasoning is what makes Greater Than Sudoku such a rewarding solving experience.
Greater Than Sudoku has its roots in the broader tradition of constraint-based logic puzzles. The idea of using inequality signs to define relationships between cells has been explored in various puzzle formats, but its application to Sudoku became popular in the mid-2000s as the Sudoku craze generated demand for new and interesting variants.
The variant has been a regular feature in puzzle competitions organized by the World Puzzle Federation and appears in puzzle magazines across Europe and Asia. Its visual clarity and logical elegance make it a natural choice for competition settings, where solvers must quickly parse and exploit constraint information under time pressure. Greater Than Sudoku continues to be a popular choice in both casual and competitive puzzle solving communities.
Greater Than Sudoku is a variant where inequality signs (< and >) are placed between adjacent cells in the grid. These signs indicate which of the two neighboring cells contains the larger digit. The puzzle typically starts with no given digits - the inequality signs are your only clues alongside standard Sudoku constraints.
In pure Greater Than Sudoku, there are no given digits at all. The solver must deduce every digit using only the inequality signs between cells and standard Sudoku rules. Some hybrid puzzles may include a few given digits to ease difficulty, but traditional Greater Than Sudoku relies entirely on the relational clues.
Inequality signs create ordering relationships between adjacent cells. By chaining multiple inequalities together, you can determine relative ordering across several cells. For example, if A > B > C in a row, you know A is at least 3, B is at least 2, and C can be 1. These chains of inequalities narrow down candidates significantly when combined with standard Sudoku elimination.
Greater Than Sudoku is generally rated intermediate difficulty. While the lack of given digits can seem daunting, the inequality signs provide substantial information. Many solvers find that once they learn to chain inequalities together, the puzzles are comparable in difficulty to a medium or hard classic Sudoku puzzle.
Start by finding the longest chains of inequalities - sequences like A > B > C > D that span multiple cells. These chains heavily constrain the possible values at each position. Also look for cells that are greater than all their neighbors or less than all their neighbors, as these must contain extreme values (high or low digits). Combine these observations with standard row, column, and box elimination.
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