I think ukimi probably translates to something like floating body; the purpose is somewhat different to 'just practicing rolling' according to this Aikido Journal interview -
Kuroda Sensei: That started about one year after I first met Kono Sensei. At that time my biggest weak point was jujutsu. I just did the movements of the kata sequentially and my uke would take the falls.
However, when I listened to my grandfather's old students talk, they would laugh and tell me this story: "It was during the war and we didn't practice jujutsu very much, but we did do a little. On those occasions, even if we were merely doing kata we thought that it would not be fun to be thrown by girls. So we tried to resist, but we were easily thrown. Then Sensei would say to us, ‘You shouldn't use power!'"
Looking back now, I realize that I trained stiffly, but even still, I was at least conscious of trying to be soft because I saw the soft ukemi [falls] of my seniors. However, no matter how aware of the problem I was, I remained stiff, even though I was trying to be soft and not use power, because my partner and I were both rigid.
Kono Sensei was the one who made me realize that. The difference between being soft and merely not using power is seen when the time comes to try to move and the technique either works or it doesn't. Also, you really have to train seriously over a period of time in order to become soft when not using power. You can't do it all at once.
Kono Sensei showed me several kirikuzushi techniques each time he came to the dojo. In these techniques he allows himself to be grabbed with two hands and I even had him teach them to my students. Later, after hearing my story about my grandfather taking forward falls thirty-six times on the length of one tatami mat, he said that he first began training with the goal of taking two falls.
When he told me this over the phone, following his lead, I began the same training. When I tried at that time it still took about seventy percent of the length of the tatami for me to fall, just as it had until that time. The only hint I had was the words of my grandfather I had heard as a boy. He said, "Roll forward and try to put your head into your crotch!" Is it that easy to put your head into your crotch? Since he was not talking about having a particular degree of body flexibility, I couldn't figure out how to roll.
Once, when I was absent from the dojo, my grandfather became disgusted at the sight of my students doing stiff jujutsu training and he showed them how to roll, saying that they could not even roll properly. On that occasion, it seems that my grandfather, who was dressed in a heavy-quilt garment, happened to take a fall. When I asked my students how he rolled they just said that they didn't know and so I had no clue. All they said was that he needed only a distance of about twelve inches to do the roll.
At that point I gave up on trying to learn this short forward roll. In order to roll forward thirty-six times in the space of one tatami, you almost have to end up in the same place each time you roll. Even though he was an old man and started from a standing position, he rolled in a space of about twelve inches in a way that was impossible to perceive with the eyes.
Kono Sensei, who is not a member of this dojo, was trying to learn this sort of lofty technique and he actually started to train. I remember at that time my eyes being opened too. Also, I think that on that occasion, when my eyes were opened to basic ukemi, I first began to reconsider jujutsu, which had been until then my weak point.
I recorded my progress in this ukemi over a period of time on videotape. I have fond recollections of my improvement. After beginning around the start of May 1988, when I could do two forward rolls, it went quickly: May 26–three times; May 29–four times; May 31–six times. Then, in June, the pace was as follows: June 3–eight times; June 9–twelve times; June 12–eighteen times; June 14–thirty-seven times; June 19–forty-three times. I don't roll in this ukemi. My leg doesn't strike the floor either. I came to understand gradually after I tried to do it.
If you watch a few clips of Kuroda sensei, you will see his jujitsu is ungodly fast - maybe his practice of ukimi has something to do with it. Anyway, it seems like an interesting thing; YMMV
This post has been edited by Doctor Horrible: 12 February 2012 - 06:12 PM