Hangetsu (Half Moon) is an intermediate shotokan karate kata. This karate kata is originally from Naha-te (Naha is a region on Okinawa and te means hand). Although very different from most shotokan kata, Hangetsu is looked at as a strong shotokan breathing and strength training kata. The first part of the kata is slow and powerful, the second part of the form is faster and more dynamic, with karate moves starting fast and then slowing right down and moves starting slow and then instantly exploding into dynamic movement.
Hangetsu is great for working on expansion and contraction. Master Gichin Funakoshi (the founder of shotokan karate) added hangetsu into the Shotokan curriculum. the main stance in this kata is hangetsu-dachi (half-moon stance), which is named so because of its semi circular movement, when stepping in this stance. The original Okinawan version of this kata is called Seisan. Many dojo have Hangetsu as a brown belt kata.