From an interview with Morihiro Saito shihan which appeared in the Aikido Today magazine #47:

Morihiro Saito Sensei: I joined Iwama Dojo in 1946. That was just after Japan had lost the war, and there were not many resources available; it was a very poor time. Born and raised in the town of Iwama, I joined the dojo when I was 18 years old. Not long afterward, a few of the Founder's uchi deshi from Hombu Dojo came to Iwama. Gozo Shioda [the Founder of Yoshinkan Aikido] moved in with his family of six (which surprised me a little). They stayed for about two years. Koichi Tohei [Founder of Ki Aikido] also came at about the same time, after being discharged from military service. I remember wondering at the time whether the war had made him tough and strong. He left the dojo when he got married. And there were two other students who became uchi deshi at the same time I did. One has since become a regional education director, and the other is now a member of the Diet. I am the only one left still hanging around Iwama! [Laughs]

Two years do not seem to be like "there one day and gone the next".