Katsuaki Asai (born 1942 in Tokyo, Japan) is a Japanese aikido teacher, the founder of the Aikikai in Germany, and the highest-ranked teacher in that country. Asai started training under aikido's founder Morihei Ueshiba aged 13, at the Hombu dojo in Tokyo, and continued during his studies at Meiji University. He was sent to Germany by Kisshomaru Ueshiba in 1965 to teach aikido, and has lived in the country ever since. His first occupation was to teach aikido to policemen in Münster, and he now runs a school in Düsseldorf.