# The Canterbury Puzzles

Henry Dudeney (1857-1930) was an English mathematician who is best remembered for his logic puzzles and games. He published several books that collected sets of his puzzles that appeared in magazines before and to which he added some new material. *The Canterbury Puzzles* (1907) was his first collection. The title refers to the fact that the first set of the puzzles are presented as if formulated by characters from Chaucer's *Canterbury Tales*. Ten years later he had another collection published *Amusements in Mathematics* (1917). In the 1920's two more collections were published and more came out posthumously.

The *Canterbury Puzzles* and the *Amusements in Mathematics* are two classics and have been available as Dover Publications for some time now. More recently they were also available on ebook repositories such as *Project Gutenberg* and others. The present book is a pocket edition by Penguin that reproduces a 1919 edition of the *Canterbury Puzzles* published by Thomas Nelson and Sons. So this edition is from after *Amusements in Mathematics* was published. Although the two books contain a largely disjunct set, some of the puzzles in the *Canterbury Puzzles* are related to or are variations of puzzles that also appeared in the *Amusements in Mathematics*, so for some of the discussions, Dudeney refers in this edition to that book for some extra information or related puzzles.

The book consists of several chapters in which the puzzles are formulated and at the end of the book the solutions are given. The chapters merely differ by the context in which the puzzles are placed, not by the kind of puzzles they contain. The first chapter has the same title as the title of the book and one should be prepared to read some Chaucer's Middle English. Some of the subsequent chapters are also placed in the same realm of medieval castles and monasteries. Later it moves to a more "modern" decorum (recall though that this is written some hundred years ago at the dawn of the 20th century, which obviously is somewhat reflected in the wording and the style, and certainly in the many illustrations). There are puzzles of all sorts to be found in each chapter, geometric as well as combinatorial or even crime mysteries that have to be solved like in a whodunit mystery. Almost all of the problems are illustrated, not only to formulate the problem or the solution when it is geometric, but also with the scenes in which monks, lords, pilgrims, or other persons are figuring. Also the degree of difficulty is rather diverse. Mathematical education is not really needed, simple counting suffices. The problems primarily rely on creative and careful logic thinking. The keywords in the index that was added to this 1919 edition should make it possible to look up a certain (type of) puzzle among the 114 items that the book contains.

One of the puzzles is the famous Haberdasher puzzle that was formulated by Dudeney in 1902. The problem is to cut up an equilateral triangle into four pieces that have to be rearranged to form a square. The solution given by Dudeney is in the form of a hinged dissection puzzle. Hinged dissections became later a particular type of puzzles. Gregg Frederickson published a couple of books on this kind of problems. Also Martin Gardner has discussed it and he wrote a tribute to Dudeney in his *Scientific American* columns. Of course Gardner also published several collections of his puzzles. The Haberdasher problem also features in *The Penguin book of curious and interesting puzzles* (1992) by David Wells which is another collection of classical puzzles. *The Moscow puzzles* (1956) by Boris Kordemsky is yet another classic that was very popular in the Soviet Union. It will also be republished by Penguin. And nowadays there are of course many more collections available on the book market of popular science and mathematics.

It is fortunate that Penguin republishes these classics and makes them available again. Dudeney was one of the first of what has become a flourishing branch of recreational mathematics and logical games and puzzles, a market that is fuelled by traditional puzzle clubs and currently the more trendy math jams.

**Submitted by Adhemar Bultheel |

**23 / Jun / 2017