🟣 How to play Renban Sudoku

By Miguel Arechaga

Renban Sudoku is a very elegant "line" variant, common in modern logic puzzles. Purple lines are drawn across the board, and the rule is simple: the numbers on each line form a group of consecutive digits, even if they're out of order. Here are the rules and a few tips.

What is Renban Sudoku?

It's a standard 9x9 sudoku with one or more renban lines drawn on it. The cells on each line must contain a set of consecutive digits with no gaps (for example 3, 4 and 5, or 6, 7, 8 and 9), placed in any order and without repeating within the line.

Rules and how to play step by step

1. The sudoku rules apply: 1 to 9 without repeats in each row, column and 3x3 box.
2. Each purple line contains a group of consecutive digits (a range with no gaps), in any order.
3. No digit repeats within a line.
4. You start with some clue cells and fill in the rest with logic. Every puzzle has a unique solution.

Tips to solve Renban Sudoku

• Think in ranges: a 3-cell line can only cover a range of 3 (1-2-3, 2-3-4 ... 7-8-9). A 5-cell one, a range of 5 (1..5 through 5..9).
• A known digit narrows the range: if a 4-cell line contains a 6, the range can only be 3-6, 4-7, 5-8 or 6-9.
• Useful extremes: a 1 forces the range to start at 1; a 9 forces it to end at 9. That pins down many lines.
• Combine each line's range with the classic elimination techniques of sudoku.

How it differs from regular sudoku

Compared to classic sudoku, Renban groups cells into sets of consecutive digits, similar in spirit to ordered-line variants but without caring about direction. If you enjoy line variants, you'll also enjoy Palindrome Sudoku.