''Dobble'' is a game in which players have to find symbols in common between two cards. It was the UK’s best-selling game in 2018 and 2019. The game is sold as ''Dobble'' in Europe and ''Spot It!'' in the US. The name is a play on the word 'double'.

Gameplay

The game uses a deck of 55 cards, each printed with eight different symbols. Any two cards always share one, and only one, matching symbol. The objective of the game is to be the first player to announce the common symbol between two given cards.

Development

In 1976, inspired by

Kirkman's schoolgirl problem Kirkman's schoolgirl problem is a problem in combinatorics proposed by Rev. Thomas Penyngton Kirkman Thomas Penyngton Kirkman FRS (31 March 1806 – 3 February 1895) was a British mathematician and ordained minister of the Church of England. ...

, French mathematics enthusiast Jacques Cottereau devised a game consisting of a set of 31 cards each with six images of insects, with exactly one image shared between each pair of them. In 2008, journalist and game designer Denis Blanchot found a few of the cards from the "game of insects" and developed the idea to create ''Dobble''. ''Dobble'' was released in France in 2009, and in the UK and North America in 2011 under

Blue Orange Games Blue Orange Games is a board game company based in San Francisco, California. They have been publishing and promoting award-winning games for over 18 years. The company was founded in 1999 by Thierry Denoual and Juilen Mayot. The company is kno ...

. In 2015, the French board game company

Asmodee Asmodee is a French publisher of board games, card games and role-playing games (RPGs). Founded in 1995 to develop their own games and to publish and distribute for other smaller game developers, they have since acquired numerous other board game ...

acquired the rights to ''Dobble'' and ''Spot It!''.

Mathematics

The special way that symbols are arranged on ''Dobble'' cards can be understood using geometry. If each card is represented by a line, and each symbol by a point where two lines intersect, then the properties of ''Dobble'' are that: * any two lines intersect at exactly one point, and * any two points are joined by exactly one line. This geometric structure is an example of a finite projective plane. If there are 3 points in each line this creates a structure known as the

Fano plane In finite geometry, the Fano plane (after Gino Fano) is a finite projective plane with the smallest possible number of points and lines: 7 points and 7 lines, with 3 points on every line and 3 lines through every point. These points and lines ...

. This represents a simpler version of ''Dobble'' with 3 symbols on each card, 7 cards and 7 symbols. In general, a finite projective plane of order n has n+1 points on each line, and n²+n+1 points and lines. This implies that a finite projective plane of order n-1 has n points on each line, and n²-n+1 points and lines. The real game of ''Dobble'' with 8 symbols on each card corresponds to the finite projective plane of order 7, where each line joins 8 points. This results in a structure with 57 lines and 57 points (7²+7+1=8²-8+1=57), corresponding to 57 cards and 57 symbols. However, the game works fine with fewer cards too, and ''Dobble'' is marketed with 55 cards in the deck (but 57 different symbols). A junior version of ''Dobble'' is marketed with 6 symbols per card, 30 cards, and 31 different symbols (6²-6+1=31).

External links

Puzzlewocky: Finite Projective Planes and the Math of Spot It!

Mathematical Association of America: The Intersection Game

Peter Collingridge - The Mathematics of Dobble

How does Dobble (Spot It) work?

References

{{Reflist Board games