In august 2016 I got the splendid book "Exotische sudoku's" by Aad Thoen and Aad van de Wetering.

You can order this book e.g. at
In the section Curiosa the following nice sudoku appears which is quite suitable for Valentineís Day. It contains no pentominoes, yet it requires a lot of puzzling.
The sudoku contains three 3x3 semi-magic diamonds in the form of a heart. A 3x3 diamond is semi-magic when its six diagonals all have the same (so-called magic) sum.

The magic sum in each of the three 3x3 diamonds is equal to 15.

Correct solutions earn eternal fame.
Send your solution to:
Name Country
Aad Thoen The Netherlands
Aad van de Wetering The Netherlands
Odette De Meulemeester Belgium
Sander Waalboer The Netherlands
Martin Friedeman The Netherlands
Lisan Sanders The Netherlands
George Sicherman USA
Luc Gheysens and Ingrid Callens Belgium
Ilse De Boeck Belgium
Bob Henderson USA
Edo Timmermans The Netherlands
Nico Looije The Netherlands
Peter Jeuken The Netherlands
Matthijs Coster The Netherlands

Bob Henderson:"I found a few semi-magic diamonds and tried putting them into the Heart-Sudoku. It took my solver about one second to find this unique solution. Thank you for sharing this puzzle with me!"

Many more sudokuís containing magic squares (of various sizes) can be found in the book "Exotische sudoku's".
Do you know our site on
pento-magic squares? It was constructed for a contest in the magazine Pythagoras

In the math magazine Pythagoras of november 2005 the article "SUDOKU light" appeared.
Question 4 was quite familiar to us. Had the writers found their inspiration on our site? It looked a lot like our
potpourri-probleem 1

On the occasion of that we all together made a pento-sudoku.
For the purpose of Valentineís Day they got a different appearance.
Place the hearts in such a way that every color appears once in every row, every column and every pentomino.

To see the solution you can click each time on the puzzle.

Many thanks to Aad van de Wetering who helped us to determine the puzzles with as few as possible numbers given at the start.
On his advice this time our puzzles contain five different pentominoes and we did not use the I and P. Then still seven different possibilities remain for the squares.

Jimmy en Sammy