Some authors have considered that guidance may be most effective in early practice when the task is unfamiliar to the learner. However, we predicted that guidance might not be effective even in the early practice period, or in performance and learning when acquiring an unfamiliar task. We planned to examine the above two points by having subjects learn a new bimanual coordination task, in which they were instructed to make a circle on a monitor screen in the 90 degree relative phase. We set up four groups; 1) control, 2) guidance, 3) observation learning, 4) advance organizer. The advance organizer group was provided the following information before leaning. (1) The movement of the right hand reflects horizontal movement on the monitor and movement of the left hand reflects vertical movement. (2) The meaning of in-phase, anti-phase, and 45 and 135 relative phase were also explained. An expert model was used for observation learning. Subjects were instructed to watch the model's movement anywhere. The guidance group and the observation learning group performed one trial by themselves after one guidance or observation trial each on the first day. They performed fhree trials by themselves after one guidance or observation trial on the second day; and ther performed all trials by themselves on the third day. The retention test was performed one week after the third day.Five trials were performed in the retention test. The results were as follows: 1) Every grup improved from the first day to the third day. 2) In the perfofmance on the third day, the guidance group showed significantly worse performance than the other groups. 3) In the retention test, the advance organizer group performed significantly better than the other groups, and the control group performed significantly better than the guidance group. Thus it was shown that guidance was not effective even in early practice when the task was unfamiliar to the learner. It was also shown that guidance was not effective for learning or performance when acquiring an unfamiliar task. The advance organizer relaked to time structure on the monitor was most effective for acquisition of the task.