These patents remained on all Monopoly games until 1941 when the Magie patent expired and was removed.1936 was a busy year for Parker Brothers and their Monopoly game.It is the first to be wholly manufactured by Parker Brothers and is very similar to the Darrow version, except for the addition of player pieces and a redesign of Darrow's black box.It was produced in limited numbers for only a few months in mid-1935.In 1935, Parker Brothers (PB) bought the rights to Monopoly from the 'inventor', Charles Darrow. PB immediately began selling Monopoly games using the Darrow game parts.The first games Parker Brothers made were marked TRADE MARK. This included a small number of the No 9 long box, very rare today.As far as I know, less than a dozen of these game boxes exist today.
These patents also appeared on the several new varieties introduced by Parker Brothers throughout 1936.Parker Brothers had an office in London and included this city on the labels of their Monopoly games.That office closed in 1940 and London was replaced by Chicago.It is estimated that over 100,000 'Patent Pending' games could have been made.No Number 9 White Box games are known with the PATENT PENDING statement on the box. After purchasing rights for Monopoly from Charles Darrow, research discovered another game very similar to Monopoly had been patented in 1924 by Elizabeth Magie.