 Kukkiwon-style taekwondo uses a series of nine forms for dan-level black belts; this series is called the "yudanja" series.The first form in the series, Koryo, was replaced by a new form of the same name in 1971, as part of the transition from the palgwae to taegeuk forms.The general meaning of this form and associated trigram is Yang, which represents Heaven and Light.