"challenging, funny, strange, addictive" Word Surfing
"entertaining, challenging, and addictive" Puzzle Monster
Letterbox is a free online word game that pits you against the computer. The letters are chosen randomly, and there are so many possible combinations that you will almost certainly never play the same game twice, no matter how addicted you become!
The computer makes its moves based on the same information you have. It doesn't "know" what letters are coming up. If you find it frustrating that the computer does so well, remember that it will never get any better at the game, but you - with contant practice - can keep improving your game.
Letterbox is a creation of Lexigame.com, founded by Alan Walker in Australia. Lexigame's aim is to produce word games unlike any others currently available.
The Letterbox online game was based on a paper and pencil game of the same name. Letters were chosen at random, one at a time, and two or more players would place each letter in their grids before the next letter was selected.
The ultimate sources of the game are shrouded in mystery, but the games described below may have been influences. Whatever the sources of Letterbox may have been, it is only on this site that it is available as an online game.
In the 1980s, the Seven Network in Australia broadcast a television game show called $50,000 Letterbox, (originally $25,000 Letterbox) in which contestants placed letters into a 4 by 4 grid, trying to make words across and down. In the TV version, the letters would always permit an arrangement that made a four-letter word in every row and column. If a player placed the letters into this arrangement they won the $50,000 prize. There's a publicity photo from the show on Flickr.
See here and here for more details. From the latter link, it seems the show in the 80s was based on a 1963 show on the same Australian network. A correspondent reported seeing a similar show in the US in the 1960s, but couldn't remember its name.
Paul Makin, who hosted $50,000 Letterbox, broadcast a radio segment on Sydney's 2UE on 23 June 2007, recalling the TV show. In it he interviewed Alan Walker, the founder of this website, about the Letterbox online game. He also played some of the soundtrack from the TV show in 1981 when a contestant filled in this grid correctly and won the big prize:
(Kook meaning an eccentric person, and otto meaning a perfume or essential oil - also known as attar. The game on this website recognises kook, but not otto, as it is considered too obscure.)
There was surely a connection between this TV show and the Letterbox paper and pencil game, since the perfect square feature was the main difference in the game design. But which came first is not known.
On the other hand, there seems to be no connection to the Letterbox TV show produced in 2009 by National Indigenous Television in Australia. This admirable venture - designed to encourage Aboriginal children to improve their spelling and grammar skills - includes a variety of word games, but doesn't seem to feature one like the Letterbox game on this site.
A game similar to Letterbox is described in some game books under a variety of names, including "Word Squares" or (confusingly) "Crossword". This is a pencil and paper game for multiple players, usually played on a 5 by 5 or larger grid. The key difference from Letterbox is that the letters are not random, but are chosen by each player in turn, the aim being to make it hard for everybody else, while setting up opportunities for yourself.
There is a good description of this game on David Parlett's website, where it is called Wordsworth.
Lexicon is a word game using special playing cards, invented in the 1930s by writer David Whitelaw. One of the games that could be played with the Lexicon cards, "Criss Cross", was similar to Letterbox. Letter cards were drawn at random, one at a time, and players had to write each letter into a 5 by 5 grid. Enthusiast Paul Mackenzie has a Web page dedicated to Criss Cross: "It is like playing Scrabble on a very small board without being allowed to swap your letters!"
Lexicon is still on sale - try here, for example, or check your local games shop, or use a search engine.
Although not a word game, Poker Squares is quite possibly the ultimate inspiration for all the games described above. It is a type of patience/solitaire where playing cards drawn one at a time are laid out in a 5 by 5 array, the aim being to make the best possible set of ten poker hands in the rows and columns. This game has been around for decades: David Parlett advises that it is described, under the name "Patience Poker" in a 1913 edition of Hoyle's Games. The rules for a multi-player version are given on this site.