The so-called Jotto problem--construct five five-letter words out of 25 different letters--was examined in the first issue of Word Ways on February 1968. Why is it called this? If one's guess word in the two-person game of Jotto is scored 0 (no letters in common with the target word), one's next guess should be a word containing no letters in common with the first one.
Eckler, A. Ross
"A New Look at the Jotto Problem,"
Word Ways: Vol. 29
, Article 5.
Available at: http://digitalcommons.butler.edu/wordways/vol29/iss4/5