Unolingo

Unolingo was created by Ian Mailing, a computer science graduate of the University of Michigan, who developed the idea in 2008 and later reworked it to cover a wider range of difficulty. Andrews McMeel Universal syndicates it, and on the web it is one of the Puzzle Society games on GoComics; some newspapers carry it on their own puzzle pages too.

Its publisher compares it to sudoku with letters in place of numbers. The grid is a 10x10 crossword shape with many letters already in place, and 26 squares left blank. There are no clues. Each of the 26 letters of the alphabet goes into exactly one blank, and every across and down word has to come out as a real word. In the game's art, partial words such as TA_ED, _UVE and STA__ wait for their missing letters.

Because each letter can be used only once, the puzzle mixes vocabulary with deduction: Q, X, Z and J have only a few possible homes, and placing them early often settles the rest. The Puzzle Society notes that by Saturday the difficulty climbs to four out of four stars.

Unolingo is included with a GoComics subscription. It suits players who like codewords and fill-in puzzles as much as crosswords.