Bonanza is an American western television series developed and produced by David Dortort and broadcast in the United States for 14 seasons on the NBC network. The entire run of the series' 431 hour-long episodes was produced in color. The premiere was on September 12, 1959, and the final episode broadcast on January 16, 1973. In its initial season, Bonanza aired on Saturday evenings and placed at number 45 in the Nielsen ratings. During its second season, the series moved up to number 17. Bonanza was moved to Sunday nights at 9:00 PM at the start of its third season. In that time slot, the ratings soared and the series become second only to Wagon Train as the most popular program on American prime time television. It remained in the top ten of the ratings until its twelfth season and ranked at number one in its sixth, seventh, and eighth seasons. Bonanza also became a worldwide success as it was broadcast in nearly 50 countries, including Canada, Brazil, Yugoslavia, the United Kingdom, France, Italy, Switzerland, Saudi Arabia, Thailand, Australia, and Japan.Bonanza is set around the Ponderosa Ranch near Virginia City, Nevada and chronicles the weekly adventures of the Cartwright family, consisting of Ben Cartwright (Lorne Greene) and his three sons (each by a different wife), Adam (Pernell Roberts), Eric "Hoss" (Dan Blocker), and Joseph (Michael Landon). Veteran actor Victor Sen Yung played the ranch cook, Hop Sing. In 1964, Pernell Roberts began expressing a desire to leave the series, and so prospective replacements were introduced via Barry Coe as Little Joe's wayward maternal half-brother Clay, and Guy Williams as Ben's nephew Will Cartwright. However, Roberts was persuaded to complete his contract, and remained through season six. The characters of Clay and Will were discontinued. In the ninth season, David Canary was added to the cast as ranch hand/foreman Candy Canady. After four years with the series, Canary left due to a contract dispute. In the twelfth season, Mitch Vogel joined the cast as Jamie Hunter, a teenage orphan who is adopted by Ben Cartwright. Following Dan Blocker's death in May 1972 after season thirteen ended, Greene, Landon, and Vogel continued the series into a fourteenth season, with Canary returning as Candy (reportedly approached by Landon) and Tim Matheson was introduced as ex-prisoner and newly hired ranch-hand Griff King. The program was moved to Tuesday nights where it slipped badly in the ratings to number 52 and was subsequently cancelled. Bonanza has, however, continued to be popular in syndication. From 1964–1967, " Bonanza " became the most watched show in the U.S. The first eleven seasons have been released on DVD in Region 1.