Str8ts

A hand made prototype of Str8ts which used black cells and the new rule of straights in compartments was invented by Canadian puzzle designer Jeff Widderich in 2007.

The puzzle has appeared in Süddeutsche Zeitung since March 2010, and in the Saturday edition of Die Rheinpfalz since August 2010.

[4] Widderich appeared with the game in the fifth season of the Canadian television show Dragons' Den on November 24, 2010, where he made a deal for a $150,000 investment in return for 10% royalties, from three of the panelists.

Additional clues are set in some of the black cells – these numbers remove that digit as an option in the row and column.

The grade is determined by a combination of opportunities to solve at each stage and the difficulty of the strategy that grants each solution.