Original: The core martial art from which aikido derives is DaitÅ - ryÅ "aiki-j Å" jutsu, which Ueshiba studied directly with Takeda Sokaku, the reviver of that art.
Simplified: Aikido is based on the martial art of DaitÅ - ryÅ "Aiki-j Å" jutsu, but began to separate from it in the late 1920s, partly due to Ueshiba's involvement with the Å moto-ky Å religion. Ueshiba's early students' records use the name aiki-j Å "jutsu.