Sudoku XV combines classic Sudoku with 'v' and 'x' Roman numeral markers which indicate that touching pairs of squares sum to either 5 or 10 respectively.

All possible pairs which sum to either 5 or 10 are marked, so if there is no 'v' and no 'x' then two squares do not sum to either 5 or 10.

As with all Sudoku puzzles, there is a unique solution which can be reached via reasonable logical deduction.

Related Sudoku variations (click for details and samples):

Consecutive Sudoku

Extra Region Sudoku

Inequality Sudoku

Jigsaw Sudoku

Kropki Sudoku

Odd Pair Sudoku

Sudoku

Sudoku Offset

Sudoku-X

Toroidal Sudoku

Sample Sudoku XV puzzles (click to view press-ready PDF version):

Example Solution

Sudoku XV

Sudoku XV 6x6

Reasoning & Logic puzzles

Choose a main puzzle type to view sub-categories, variations and samples:

3D Sudoku

Binary Puzzle

Calcudoku

Dominoes

Easy as ABC

Fences

Futoshiki

Hanjie

Hashi

Heyawake

Hitori

Kakuro

Killer Sudoku

Masyu

Numberlink

Nurikabe

PivotPix

Rectangles

Samurai Sudoku

Skyscraper

Slitherlink

Star Battle

Sudoku

Tapa

Yajilin