Yellow Bamboo is a form of white magic/martial art developed in Bali. If you sign up to get the free Yellow Bamboo training video
then "you can learn very powerful methods to protect yourself and others. If you watch the videos you will see that it is possible to knock down attackers without touching them. This is a very powerful form of personal development."
Annoyed by these extravagant claims (particularly the one about being able to knock down opponents without touching them), some Jiu-Jitsu practitioners decided to challenge the local Yellow Bamboo masters to a test "to prove once and for all that no-touch or Chi knockouts are, and have always been, complete and utter bullshit."
These were the guidelines for the test: "The YB practitioner assumes a stance on the sand and is given time to prepare his Chi in accordance with YB practices. The challenger then runs 20 feet across the sand and attacks the YB practitioner. As the challenger is making his run, the YB practitioner has to effectively disable or deflect him using his chi."
Needless to say, the Yellow Bamboo people completely failed the test