rendering the Official Scrabble Players Dictionary less fit for official Scrabble play. The OSPD is available in bookstores, while the NWL is available only through NASPA. Collins Scrabble Words In all other English-speaking countries, the competition word list is Collins Scrabble Words 2019 edition, known as CSW19. (Versions of this lexicon before 2007 were known as SOWPODS.) The lexicon includes all allowed words 2 to 15 letters long. Historically, this list has contained all OTCWL words plus words sourced from Chambers and Collins English dictionaries, but recent editorial decisions have caused greater discrepancies between CSW and NWL. This book is used to adjudicate at the World Scrabble Championship and all other major international competitions outside North America. Tournaments are also played using CSW in North America, particularly since Hasbro ceased to control tournament play in 2009. NASPA officially rates CSW tournaments alongside NWL tournaments, using a separate rating system. Challenges The penalty for a successfully challenged play is nearly universal: the offending player removes the tiles played and forfeits their turn. (In some online games, an option known as "void" may be used, wherein unacceptable words are automatically rejected by the program. The player is then required to make another play, with no penalty applied.) The penalty for an unsuccessful challenge (where all words formed by the play are deemed valid) varies considerably, including: "Double Challenge", in which an unsuccessfully challenging player must forfeit the next turn. This penalty governs North American (NASPA-sanctioned) OWL tournament play, and is the standard for North American, Israeli, and Thai clubs. Because loss of a turn generally constitutes the greatest risk for an unsuccessful challenge, it provides the greatest incentive for a player to "bluff", or play a "phony" – a plausible word that they know or suspect to be unacceptable, hoping their opponent will not challenge it. Or a player can put down a legal word that appears to be a phony hoping the other player will incorrectly challenge it and lose their turn. "Single Challenge"/"Free Challenge", in which no penalty whatsoever is applied to a player who unsuccessfully challenges. This is the default rule in Ireland and the United Kingdom, as well as for many tournaments in Australia, although these countries do sanction occasional tournaments using other challenge rules. Modified "Single Challenge", in which an unsuccessful challenge does not result in the loss of the challenging player's turn, but is penalized by