How to play:
This puzzle uses a double-six set of dominoes.
On the playing board the domino numbers are shown but the dominoes are missing.
The object of the puzzle is to set all the dominoes (which fit exactly) on the board.
Click on any two adjacent numbers, across or down, to set a domino.
If your first click is wrong, click again to undo.
Be certain that the puzzle can be solved by logic, not guesswork! I can give you a hint if you can't get started.
Dominoes originated in China before being brought to Europe in the early eighteenth century.
Dominosa is a German puzzle, according to Martin Gardner, invented by O.S. Adler in 1874.
It was patented by Richard Osa (pseudonym for O.S. Adler) in Germany in 1893 as German Reichs Patent No. 71539 and
he published it in 1894 under the name of "Dominosa" combining 'Domino' with his initials.
It later appeared in a domino puzzle book in 1912 co-authored by Fritz Jahn.