Morihei Ueshiba (植芝 盛平 Ueshiba Morihei?, December 14, 1883 – April 26, 1969) was a famous martial artist and founder of the Japanese martial art of aikido. He is often referred to as "the founder" Kaiso (開祖?) or Ōsensei (大先生/翁先生?), "Great Teacher".
The son of a landowner from Tanabe, Ueshiba studied a number of martial arts in his youth, and served in the Japanese Army during the Russo-Japanese War. After being discharged in 1907, he moved to Hokkaidō as the head of a pioneer settlement; here he met and studied with Takeda Sokaku, the founder of Daitō-ryū aiki-jūjutsu. On leaving Hokkaido in 1919, Ueshiba joined the Ōmoto-kyō movement in Ayabe, serving as a martial arts instructor and opening his first dojo. He accompanied the head of the Ōmoto-kyō sect, Onisaburo Deguchi, to Mongolia in 1924. The following year, he experienced a great spiritual enlightenment, stating that, "a golden spirit sprang up from the ground, veiled my body, and changed my body into a golden one." After this experience, his martial arts skill appeared greatly increased.
Ueshiba moved to Tokyo in 1926, where he set up the Aikikai Hombu Dojo. In the aftermath of the Second World War the dojo was closed, but Ueshiba continued training at another dojo he had set up in Iwama. From the end of the war until the 1960s, he worked to promote aikido throughout Japan and abroad. He died from liver cancer in 1969.