The American Ninja Challenge and American Ninja Warrior are the preliminary trials hosted by to determine the representatives for SASUKE. The trials started in the Summer of 2007 for SASUKE 19 and continue to this day. The fifth American Ninja Challenge has been renamed American Ninja Warrior and has subsequently taken over as the primary format for the American Ninja qualifiers. Subsequently, the regionals and Finals have been picked for airing by NBC.
American Ninja Challenge
The first American Ninja Challenge was held in the Summer of 2007 for SASUKE 19. Potential competitors were asked to submit videos to  which would then be selected by G4. G4 then selected the ten videos and let the viewers choose the top three. The top three selections were then flown to Los Angeles to compete in a series of trials to test the contestants speed, strength, and endurance. The winner would be flown to Japan to compete in SASUKE 19. The finalists were Brett Sims, Colin Bell, and Bryant Powers.
American Ninja Challenge 2
The second American Ninja Challenge was held in conjunction with SASUKE 20 in the spring of 2008 shown in daily segments over a week on G4's Attack of the Show. As with last time, potential competitors were asked to submit videos to  which would then be selected by G4. Viewers were then asked to vote for their top six, who were then collectively flown out to Marine Corps Base Camp Pendleton in Southern California to compete on a marine training obstacle course in three 1v1 intervals aired daily while G4 correspondent Zach Selwyn narrated the action. The winners of those intervals were later taken to a SASUKE-inspired obstacle course, dubbed the Ninja Killer. The two top times were then flown to Japan to compete in SASUKE 20. Notable SASUKE American contestant Paul Terek was on hand during the competition to give input on the finalists along with Selwyn while Master SGT. Christopher Marano oversaw the training course in the "first round". Day 1 of airing was used to hype up the challenge along with providing information on the details, many of which were later repeated with day 2 and onward actually progressing through the competiton. The six finalists were Brian Orosco, Rick Seedman, Mark Witmer, Joe Simonsen, Levi Meeuwenberg, and Ruselis Perry.
American Ninja Challenge 3
American Ninja Challenge returned in the summer of 2008. This time the competitors were not flown out to LA, but instead were announced during an episode of Attack of the Show. From the finalists, viewers were asked to vote and the top three would join Levi Meeuwenberg and Attack of the Show! hosts, Olivia Munn and Kevin Pereira. Past winners like Brian Orosco, Colin Bell entered videos. Brian Orosco and Mark Witmer won two of the three spots, as they both competed on the ANC 2 course. Joining them was the only female winner to date, Luci Romberg.
American Ninja Challenge 4
American Ninja Challenge returned for a fourth time in the winter of 2008 and the early parts of 2009. Like ANC3, the competitors were not flown out to Los Angeles. Potential contestants were asked to send in videos and the winner would be "selected" by Olivia Munn. The winner was David Campbell, who had been trying to compete since ANC2. He was joined by returning competitors Olivia Munn, Luci Romberg, and Levi Meeuwenberg.
American Ninja Warrior 1
The popularity of the American Ninja Challenge led G4 to create an licenced version of SASUKE, titled American Ninja Warrior, with all contestants from the United States and all play-by-play commentary in English. The tryouts and semi finals competitions were filmed in the United States. The top 30 from the six-obstacle qualifying round advanced to the semifinal, where the top 15 times through an extended nine-obstacle course participated in a final round on the beach to determine the 10 qualifiers for SASUKE 23.
American Ninja Warrior 2
A second American Ninja Warrior was held by G4 for SASUKE 26. The qualifying round and semifinal was held in Windward Plaza at Venice Beach, California on August 7 and 8. Following that was a new feature, a four-day boot camp in the California mountains where competitors trained on replicas of SASUKE obstacles such as the Cliffhanger and Floating Boards. After each day, one to two competitors were eliminated via the Heavenly Ropes.
Also at the events were SASUKE All-Star Nagano Makoto, Shin Sedai Urushihara Yuuji, and Okuyama Yoshiyuki. Each were there to sign autographs, and all three got to run the qualifying round course. Both Okuyama and Urushihara cleared, but Nagano failed the jump to the Jumping Bars.
American Ninja Warrior 3
A third American Ninja Warrior was held in the spring of 2011 as a qualifier for SASUKE 27. Like the previous tournament, the qualifying round and semifinal was held at Venice Beach, and was followed by a four-day boot camp in the California mountains. The grand prize was increased from $250,000 to $500,000. In addition, the Japan finals were aired on NBC as part of a two-hour special.
American Ninja Warrior 4
Following the success of American Ninja Warrior 3, and with the future of SASUKE uncertain, G4 and NBC held American Ninja Warrior 4 in spring 2012. Unlike the previous three American Ninja Warrior tournaments, six regional tournaments were held at three sites - Venice Beach in Los Angeles, Fair Park in Dallas, Texas, and the campus of Florida International University in Miami, Florida. Within each region, the traditional American Ninja Warrior format was followed; the top 30 from a six-obstacle qualifying course were narrowed to the top 15 from a nine-obstacle semifinal course. The top 15 from each of the six regions, plus 10 wild cards selected by G4, competed in a full-scale four stage SASUKE course built in Las Vegas, Nevada. The Vegas course mainly followed SASUKE 27 with a few minor changes.