Sudoku-4 Thumbnail of a Sudoku-4 puzzle.

Size:
4x4.
Elements:
1, 2, 3, and 4.
Groups: Twelve total.
The 4 rows.
The 4 columns.
The 4 2x2 squares.
Instructions:
Precise details on group numbering.
Answer grids:
There are 288 answer grids,
(including all possible symetrically equivalent grids)

Puzzle Difficulty levels and Examples

Difficulty LevelLowHighExample
Easiest 2 2 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid
Easy 3 3 Puzzle   ·   3-steps   ·   All-steps   ·   Solution grid

Derived Signature Puzzles:

Puzzle NamePuzzle
Abel Thumbnail of a Abel puzzle.
Alex Thumbnail of a Alex puzzle.
Andy Thumbnail of a Andy puzzle.
Beth Thumbnail of a Beth puzzle.
Bret Thumbnail of a Bret puzzle.
Chad Thumbnail of a Chad puzzle.
Chet Thumbnail of a Chet puzzle.
Cody Thumbnail of a Cody puzzle.
Cris Thumbnail of a Cris puzzle.
Dale Thumbnail of a Dale puzzle.
Dave Thumbnail of a Dave puzzle.
Dawn Thumbnail of a Dawn puzzle.
Dean Thumbnail of a Dean puzzle.
Doug Thumbnail of a Doug puzzle.
Earl Thumbnail of a Earl puzzle.
Elmo Thumbnail of a Elmo puzzle.
Eric Thumbnail of a Eric puzzle.
Evan Thumbnail of a Evan puzzle.
Fonz Thumbnail of a Fonz puzzle.
Fran Thumbnail of a Fran puzzle.
Fred Thumbnail of a Fred puzzle.
Gabe Thumbnail of a Gabe puzzle.
Gaby Thumbnail of a Gaby puzzle.
Gail Thumbnail of a Gail puzzle.
Gary Thumbnail of a Gary puzzle.
Gina Thumbnail of a Gina puzzle.
Glen Thumbnail of a Glen puzzle.
Gwen Thumbnail of a Gwen puzzle.
Hank Thumbnail of a Hank puzzle.
Hans Thumbnail of a Hans puzzle.
Herb Thumbnail of a Herb puzzle.
Hope Thumbnail of a Hope puzzle.
Ivan Thumbnail of a Ivan puzzle.
Jack Thumbnail of a Jack puzzle.
Jake Thumbnail of a Jake puzzle.
Jane Thumbnail of a Jane puzzle.
Jean Thumbnail of a Jean puzzle.
Jodi Thumbnail of a Jodi puzzle.
Jody Thumbnail of a Jody puzzle.
John Thumbnail of a John puzzle.
Josh Thumbnail of a Josh puzzle.
Jude Thumbnail of a Jude puzzle.
Judy Thumbnail of a Judy puzzle.
Karl Thumbnail of a Karl puzzle.
Kate Thumbnail of a Kate puzzle.
Katy Thumbnail of a Katy puzzle.
Kent Thumbnail of a Kent puzzle.
Kris Thumbnail of a Kris puzzle.
Kurt Thumbnail of a Kurt puzzle.
Kyle Thumbnail of a Kyle puzzle.
Lacy Thumbnail of a Lacy puzzle.
Lisa Thumbnail of a Lisa puzzle.
Lois Thumbnail of a Lois puzzle.
Lucy Thumbnail of a Lucy puzzle.
Luke Thumbnail of a Luke puzzle.
Mark Thumbnail of a Mark puzzle.
Mary Thumbnail of a Mary puzzle.
Mick Thumbnail of a Mick puzzle.
Mike Thumbnail of a Mike puzzle.
Milo Thumbnail of a Milo puzzle.
Nate Thumbnail of a Nate puzzle.
Nick Thumbnail of a Nick puzzle.
Noah Thumbnail of a Noah puzzle.
Noel Thumbnail of a Noel puzzle.
Orin Thumbnail of a Orin puzzle.
Owen Thumbnail of a Owen puzzle.
Page Thumbnail of a Page puzzle.
Paul Thumbnail of a Paul puzzle.
Phil Thumbnail of a Phil puzzle.
Reba Thumbnail of a Reba puzzle.
Rick Thumbnail of a Rick puzzle.
Rita Thumbnail of a Rita puzzle.
Rose Thumbnail of a Rose puzzle.
Rudy Thumbnail of a Rudy puzzle.
Ruth Thumbnail of a Ruth puzzle.
Ryan Thumbnail of a Ryan puzzle.
Scot Thumbnail of a Scot puzzle.
Sean Thumbnail of a Sean puzzle.
Stan Thumbnail of a Stan puzzle.
Suzy Thumbnail of a Suzy puzzle.
Thea Thumbnail of a Thea puzzle.
Theo Thumbnail of a Theo puzzle.
Thom Thumbnail of a Thom puzzle.
Tina Thumbnail of a Tina puzzle.
Toby Thumbnail of a Toby puzzle.
Tony Thumbnail of a Tony puzzle.
Trey Thumbnail of a Trey puzzle.
Vern Thumbnail of a Vern puzzle.
Walt Thumbnail of a Walt puzzle.
Wash Thumbnail of a Wash puzzle.
West Thumbnail of a West puzzle.
Yale Thumbnail of a Yale puzzle.
Yank Thumbnail of a Yank puzzle.
Yard Thumbnail of a Yard puzzle.
Ynez Thumbnail of a Ynez puzzle.
York Thumbnail of a York puzzle.
Yule Thumbnail of a Yule puzzle.
Zack Thumbnail of a Zack puzzle.
Zane Thumbnail of a Zane puzzle.